Summary

Piero di Benedetto de' Franceschi, known as Piero della Francesca (Borgo del Santo Sepolcro, in the upper Tiber valley, ca. 1415-Borgo del Santo Sepolcro, October 12, 1492) was an Italian painter of the Quattrocento (15th century). Today he is appreciated above all as a painter specializing in frescoes, but in his time he was also known as a geometrician and mathematician, a master of perspective and Euclidean geometry, subjects on which he concentrated from 1470 onwards. His painting was characterized by his serene style and use of geometric forms, particularly in relation to perspective and light. He is one of the main and fundamental figures of the Renaissance, although he never worked for the Medici and spent little time in Florence.

The biographical reconstruction of Piero's life is an arduous undertaking to which generations of scholars have devoted themselves, relying on the faintest hints, in the general scarcity of reliable official documents that have reached us. His own work has reached us only in fragmentary form, with numerous extremely important losses, including the frescoes executed for the Apostolic Palace, replaced in the sixteenth century by the frescoes of Raphael.

First years

Piero was born in an unspecified year between 1406 and 1420, in Sansepolcro, which Vasari calls "Borgo San Sepolcro", a region of Tuscany. This border territory, in the middle of the 15th century, changed sovereignty several times: at first it was in the hands of Rimini, then it belonged to the Republic of Florence and later it passed into the possession of the Papacy. The date of birth is unknown, because a fire in the communal archives of Sansepolcro destroyed the birth records of the civil registry. A first document that mentions Piero as a witness is a will dated October 8, 1436, from which it can be deduced that the artist must have already been at least the prescribed age of twenty for an official document. According to Giorgio Vasari in The Lives of the Most Excellent Italian Architects, Painters and Sculptors from Cimabue to our times, Piero, who died in 1492, was 86 years old at the time of his death, which would put his date of birth back to 1406 but this information is considered erroneous, since his parents were married in 1413.

Piero della Francesca came from a family of merchants, hence he knew mathematics, calculus, algebra, geometry and counting with the abacus. His father was the very rich fabric merchant Benedetto de' Franceschi, and his mother was Romana di Perino da Monterchi, a noblewoman from an Umbrian family. To this aristocratic family belonged other famous people of Italian history; thus, Francesco Franceschi (Angiolo Franceschi) and the writer Caterina Franceschi Ferrucci (1803 - 1887), daughter of Antonio Franceschi, physician and politician, and of the countess Maria Spada di Cesi.

It is not known why, shortly before his death, he was already called "della Francesca", instead of "di Benedetto" or "de' Franceschi", but Vasari's conjecture that he had taken his mother's surname because her husband died when she was pregnant and she was the one who raised him, cannot be accepted. Piero was the first-born son of the couple, who later had four other brothers (two died at an early age) and a sister.

He was an itinerant artist, who worked in various locations in central and northern Italy, in an attitude comparable to other contemporaries such as Leon Battista Alberti.

He must have had a first education within the family business, to later be trained as a painter, although it is not known for sure how, although it was probably in Sansepulcro itself, a city of cultural frontier, between Florentine, Sienese and Umbrian influences. He may have learned his art from one of the various Sienese artists who worked in Sansepulcro during his youth. It has also been suggested that he may have been trained in Umbria, where his taste for landscape painting and the use of delicate colors came from. The first artist with whom he collaborated was Antonio d'Anghiari, his father's partner in the manufacture of banners, active and resident in Sansepulcro, as attested on May 27, 1430 by a document of payment to Piero for the painting of banners and flags with the insignia of the Commune and the papal government, placed above a gate of the walls. He would collaborate with Antonio d'Anghiari between 1432 and 1436. In 1438 he is again documented in Sansepolcro, where he is mentioned among the other assistants of Antonio d'Anghiari, to whom was entrusted, at first, the commission for the altarpiece of the church of San Francesco (later realized by Sassetta). It is difficult to say if Piero trained with Antonio as a master, since no certain work of the latter has been preserved.

With Domenico Veneciano

In 1439 he is first documented in Florence, where he may have received his real training; he may have been there as early as around 1435. By then, Masaccio had already been dead for a decade. He was apprenticed to Domenico Veneziano, and is quoted on September 7, 1439 as being among his assistants on a cycle of frescoes dedicated to the Life of the Virgin in the choir of San Gili (now Santa Maria la Nuova), now lost. He met Fra Angelico, thanks to whom he had access to the work of the late Masaccio and also to other masters of the time such as Brunelleschi. The mastery of the art of perspective, the luminous painting and the very clear and sumptuous palette of Domenico Veneziano influenced Piero, but also the modern and vigorous painting of Masaccio, which shaped some of the fundamental characteristics of his later work. Piero was familiar with the various solutions that the Florentine pre-Renaissance gave to the problems of representing the human body and how to reflect three-dimensional space on a two-dimensional surface. On the one hand, the linearism and lyricism of Fra Angelico, Benozzo Gozzoli and Filippo Lippi were still in force, and on the other, there was the geometric realism of Paolo Uccello. Piero learned how to represent an atmospheric light by adding a large proportion of oil in the color mixtures.

He had probably already collaborated with Domenico in Perugia in 1437-1438 and, according to Vasari, the two also worked in Loreto, in the church of Santa Maria, this work they left unfinished and Luca Signorelli finished it.

The first surviving work is the Madonna and Child, now in the Contini Bonacossi Collection in Florence, attributed to Piero for the first time in 1942 by Roberto Longhi, dating from 1435-1440, when Piero was still working as a collaborator of Domenico Veneziano. A vase is painted on the back of the panel, as an exercise in perspective.

By 1442 Piero was back in Sansepolcro where he was appointed one of the "consiglieri popolari" of the communal council. On January 11, 1445 he received from the local Confraternity of Mercy the commission for an altarpiece for the altar of their church: the contract foresaw the completion of the work in three years and its complete autograph, although it was dilated over the next fifteen years and part of it is due to collaborators of his workshop. Still in 1462 the confraternity of Sansepolcro made a payment to Marco di Benedetto de' Franceschi, Piero's brother and his representative in his absence, on account of this altarpiece. The best known part of this altarpiece is the central panel, possibly the last to be painted, depicting the Madonna della Misericordia. The confraternity demanded that the background of the altarpiece be gilded, an archaizing and unusual feature in Piero.

One of his most famous works, the Baptism of Christ, originally the central panel of a large triptych, may well date from this early period. Its dating is controversial, to the point that some consider it to be Piero's first work. Some iconographic elements, such as the presence of Byzantine dignitaries in the background, suggest that the work is dated to around 1439, the year of the Council of Basel-Ferrara-Florence in which the churches of the West and East were ephemerally reunited. Others date the work later, around 1460.

Travel

He was soon requested by various princes. In the 1440s he was in several Italian courts: Urbino, Ferrara and probably Bologna, where he painted frescoes that have been completely lost. In Ferrara he worked between 1447 and 1448 for Lionello d'Este, marquis of Ferrara. In 1449 he executed several frescoes in the Castle of Este and the church of San Andreas in Ferrara, also lost. Perhaps he had his first contact with Flemish painting here, meeting Rogier van der Weyden directly during the latter's supposed trip to Rome or through the works he had left at court. This Flemish influence is particularly evident if one thinks of his precocious use of oil painting. Piero influenced the later Ferrarese painter Cosme Tura.

March 18, 1450 is documented in Ancona, as testified by the will (recently recovered by Matteo Mazzalupi) of the widow of Count Giovanni di messer Francesco Ferretti. In the document the notary specifies that the witnesses are all "citizens and inhabitants of Ancona", so Piero was probably a guest for a certain time of the important Anconetan family and perhaps for them he painted the tablet of penitent St. Jerome, dated precisely in 1450. From the same years comes the very similar St. Jerome and the donor Girolamo Amadi. In both there is an interest in the landscape and in the adequate representation of the details, in the variations of the materials and of the "lustre" (i.e. of light reflections), which can be explained only through a direct knowledge of Flemish painting. Vasari also recalls a painting of the Betrothal of the Virgin on the altar of St. Joseph in the cathedral, already disappeared in 1821.

In 1451 he went to Rimini, called by Segismundo Pandolfo Malatesta. He then executed, for the famous Malatesta Temple, his well-known monumental votive fresco of Pandolfo Malatesta at the feet of his patron saint, dated 1451, in which the scene is framed in a trompe l'oeil. He also made a portrait of the condotiero. Here he probably met another famous mathematician and architect of the Renaissance, Leon Battista Alberti.

In 1452, Piero della Francesca was called upon to execute, replacing Bicci di Lorenzo, what would become known as his masterpiece and one of the most significant works of the Renaissance: the frescoes of the Basilica of San Francesco in Arezzo, dedicated to the Legend of the Holy Cross. It was the Bacci family, the richest in Arezzo, who decided to decorate the choir or main chapel of the church dedicated to St. Francis. In 1447 they hired Bicci di Lorenzo, of late Gothic tradition, but he only managed to finish the fresco of the vault before he died. They then hired Piero della Francesca to finish it, dating its completion between 1452 and 1466, although it has also been considered possible that it was finished before 1459. It is very possible that he worked in two phases, a first one between 1452 and 1458, and a second one after his return from Rome. At the end of 1466 the Aretina brotherhood of the Annunciation commissioned him a banner with the Annunciation, citing in the contract the success of the frescoes of San Francisco as the reason for the commission, therefore, by that date, the cycle had to be finished. In this work we can appreciate characteristics that make Piero a precursor of the High Renaissance, such as the clear composition that masterfully employs geometric perspective, the rich and innovative treatment of light (borrowed from Domenico Veneziano) and its admirable, delicate and clear chromatism.

Mature works

The realization of the Arezzo work was simultaneous with that of other works and with his stay in other localities. Thus, in 1453, he returned to Sansepolcro where, the following year, he signed a contract for an altarpiece for the main altar of the Augustinian church, known as the Altarpiece or Polyptych of St. Augustine. He worked on this project from 1454 and it was not finished until 1469, as evidenced by the payment made, perhaps the last, on November 14 of that year. In these panels, his deep interest in the theoretical study of perspective and his contemplative approach is again evident. The work is very innovative, lacking the gold background, replaced by an open sky between classicist balusters, and with the figures of the saints of an accentuated linearity and monumentality. Currently only four panels remain.

He was also in Rome on at least two occasions. The first time, called by Pope Nicholas V (d. 1455), in which he executed frescoes in the Basilica of Santa Maria Maggiore, of which only traces remain, namely a St. Luke painted probably by his workshop, while nothing has been preserved of the entirely autograph works. The second time was when he was called by Pope Pius II, who had just been elected. Before leaving Sansepolcro, he appointed his brother Marco as his representative, in anticipation of a long absence. Pius II commissioned him to paint his room in the Apostolic Palace; this work was destroyed in the 16th century to make way for the first of Raphael's Vatican Rooms. The papal treasury issued a document, dated April 12, 1459 for the payment of 140 florins for "certain paintings" in the "chamber of His Holiness Our Lord."

Other works of maturity are the Virgin of Childbirth (1455-1465) and The Resurrection of Christ (1450-1463). The Virgin of Childbirth was painted in only seven days, for the chapel of the ancient church of Santa Maria di Nomentana in the cemetery of Monterchi, a village near Sansepolcro, where his mother was from. The iconographic model, the Virgin of Childbirth, was not very common. He used high quality materials, such as a considerable amount of navy blue obtained from imported lapis lazuli. Piero's obsession with symmetry can be seen in this work, which leads him to place two identical angels, one on each side of the Virgin, using the same cardboard. The Resurrection of Christ, on the other hand, is a remarkable work because it uses different perspectives. It was painted in Arezzo, near his hometown, while he was working on the frescoes of the Legend of the Holy Cross.

On November 6, 1459 Piero's mother died and on February 20, 1464 his father. In 1460 he was in Sansepolcro, where he signed and dated the fresco of St. Louis of Toulouse. It should be remembered that in 1462 he was paid for the Polyptych of Mercy. In 1466 Piero painted the fresco of a Magdalene in the Cathedral of Arezzo, and he was commissioned, as already mentioned, the banner for the Confraternity of the Annunciation, which he delivered in Arezzo in 1468.

In 1467 in Perugia he executed an altarpiece for the tertiary sisters of the convent of St. Anthony, known as the Polyptych of St. Anthony. He was commissioned a work of late Gothic inspiration, but in the upper part it has the highlight: the Annunciation of the gable is of clear Renaissance style, showing his mastery of perspective.

In 1468 he is documented in Bastia Umbra, where he had taken refuge to escape the plague. There he made at least one other lost painted gonfalon.

Urbino

By 1469, after finishing the frescoes of Arezzo and the altarpiece of St. Augustine, Piero was in Urbino, in the service of Federico de Montefeltro. The periods of his stay in Urbino are not clear; it seems certain that he was there between 1469 and 1472, but some authors delay his departure until 1480. It was a period in which he produced paintings of remarkable quality. Piero is considered one of the protagonists and promoters of the Renaissance in Urbino, and his own style reached in this city an unsurpassed balance between the use of rigorous geometric rules and a serenely monumental air. At the court of Urbino he deepened his knowledge of Flemish painting, both through the Duke's collection and through the presence of Justus of Ghent, who between 1471 and 1472 settled in Italy, first in Rome and then, at the invitation of Frederick of Montefeltro, at the court of Urbino, where he stayed until October 1475. He was not the only prominent artist he met in Urbino, for there he also came into contact with Melozzo da Forlì and Luca Pacioli.

Here he painted the famous double portrait of Federico de Montefeltro and his wife Battista Sforza (ca. 1465-1472), now in the Uffizi Gallery in Florence, entitled Triumph of Chastity. It shows the influence of Flemish painting in the treatment of the landscape and in the meticulousness and love for detail.

In 1469 Piero is documented in Urbino, where the Corpus Christi Confraternity commissioned him to paint a processional banner. On that occasion the master was also asked to paint the Corpus Domini Altarpiece, already commissioned to Fra Carnevale, then to Paolo Uccello (1467), who painted only the predella, and finally finished by Justus of Ghent in 1473-1474. In 1470 Federico da Montefeltro is documented in Sansepolcro, perhaps in the company of Piero.

To this period in Urbino belongs The Flagellation (ca. 1470, although others date it to 1452), one of his best-known paintings. Apparently, it was a personal creation that did not depend on any commission and that shows that Piero was aware of the architectural innovations of the time; it is controversial as to its exact meaning (see Iconic Interpretations of this painting).

In the Madonna of Senigallia, also from this period, his contact with Flemish art is evident. Also from this period is the Sacra Conversation, today called Pala de Brera because it is kept in the Pinacoteca de Brera (Milan) and is also known as the Madonna of the Duke of Urbino. It was commissioned for the church of San Donato degli Osservanti in Urbino, possibly completed around 1474. In this majestic work he places the figures in a harmonious and polychrome architectural frame reminiscent of the creations of Leon Battista Alberti, in particular the church of San Andreas in Mantua. It adopts a relatively new form in Christian iconography, that of "sacred conversation". It is very likely that the court painter Pedro Berruguete, to whose brush Roberto Longhi attributes Federico's hands, was also involved in the realization of the altarpiece.

It is believed that it was in Urbino where he painted the Nativity (1470-1485), which is currently in London. It is one of Piero's last works, when he was already going blind, and it is believed that for this reason it was left unfinished, although its condition may also be due to the restorations of past centuries. It was commissioned by his nephew, on the occasion of his marriage. Some critics hypothesize that the face of the Virgin was made by another "Flemish" hand. The Virgin and Child with four angels from the Clark Art Institute in Williamstown, Massachusetts, is also attributed to this period.

Last years

In 1473 a payment is recorded, perhaps still for the Polyptych of St. Augustine. In 1474 he received the last payment for a lost painting, destined for the chapel of the Madonna of the abbey of Sansepolcro. From July 1, 1477 to 1480 he lived, with some interruptions, in Sansepolcro, where he was a regular member of the communal council. In 1478 he painted a lost fresco for the Chapel of Mercy, still in Sansepolcro. Between 1480 and 1482 he was in charge of the Confraternity of St. Bartholomew in his hometown.

Piero della Francesca is documented in Rimini on April 22, 1482, where he rented "a mansion with a well". Here he dedicated himself to the writing of the Libellus de quinque corporibus regularibus, finished in 1485 and dedicated to Guidobaldo da Montefeltro. He made his will on July 5, 1487, declaring himself "healthy in spirit, mind and body". In his last years, painters such as Perugino and Luca Signorelli frequently visited his workshop.

Although his mathematical work is nowadays little less than completely ignored, Piero was, during his lifetime, a reputed mathematician. According to Giorgio Vasari, "...artists bestowed on him the title of the best geometrician of his times, because surely his perspectives have a modernity, a better design and a greater grace than any other." It is Vasari also who says that in these last years he was afflicted by a serious eye disease that prevented him from working. For this reason he abandoned painting and devoted himself exclusively to his theoretical work, which he wrote dictating it.

He died in Sansepolcro on October 12, 1492, the same day on which Christopher Columbus first set foot in America. He was buried in the abbey of Sansepolcro, today the Duomo.

Three very important texts written by Piero are known, among the most scientific of the 15th century: the De prospectiva pingendi ("On perspective for painting"), Libellus de quinque corporibus regularibus ("Little book of the five regular solids") and a calculus manual entitled Trattato dell'abaco ("Treatise on the abacus").

The topics covered in these writings include arithmetic, algebra, geometry and innovative works in both solid geometry and perspective. His contact with Alberti is evident in them. In these three mathematical works there is a synthesis between Euclidean geometry, belonging to the school of scholars, and mathematics with the abacus, reserved for technicians.

The first work was the Libellus de quinque corporibus regularibus, a treatise dedicated to geometry, which took up ancient themes of Platonic-Pythagorean tradition, always studied with the intention that they could be used as design elements. It is inspired by the Euclidean lessons for the logical order of the expressions, for the references and the coordinated and complex use of the theorems, while approaching the requirements of technicians for the predictability of the figures treated, solid and polyhedral, and for the absence of classical demonstrations and for the use of arithmetic and algebraic rules applied to the calculations. In the text, in particular, for the first time the regular and semi-regular polyhedra are drawn, studying the relationships that exist between the five regular ones.

In the second treatise, De prospectiva pingendi, he continued in the same line of study, but with notable novelties, to the point that Piero can be defined as one of the fathers of modern technical drawing; in fact, he preferred axonometry to perspective, considering it more congruent with a geometrical model. Among the problems he solved, the calculation of the volume of the vault and the architectural elaboration of the dome constructions stand out.

The Trattato d'abaco, on applied mathematics (calculus) was perhaps written as early as 1450, thirty years before the Libellus. The title is of modern times, because the original lacks it. The geometrical and algebraic part is very extensive in relation to the customs of his time, as well as the experimental part on which the author has explored unconventional elements.

Much of Piero's work was later included in works by others, especially Luca Pacioli, a Franciscan who was a disciple of Piero and whom Vasari directly accuses of copying and plagiarizing his master. Piero's work on solid geometry appears in Pacioli's De divina proportione (Divine Proportion), a work illustrated by Leonardo da Vinci.

Critics are divided on the collaboration of several artists in his workshop (on the other hand, the only pupil who has been documented is Galeotto da Perugia. Among his collaborators should be mentioned Giovanni da Piemonte, with whom he worked in the execution of the frescoes in San Francesco; the panel preserved near the church of Santa Maria delle Grazie in Città di Castello, in which influences of Piero della Francesca are certainly present, is by this author.

During his lifetime he was very famous and his impact was felt in later generations, even if not by painters who worked directly with him. He left several disciples and followers: besides Luca Pacioli, Melozzo da Forli and Luca Signorelli.

Piero della Francesca is a fourteenth-century painter, belonging to the second generation of Renaissance painters, intermediate between Fra Angelico and Botticelli. He assumed the findings of the first Florentine Renaissance school of authors such as Paolo Uccello, Masaccio and Domenico Veneziano. He did not travel to Flanders, but he did see Flemish painting, so he made a kind of symbiosis between Italian Renaissance and Flemish painting.

Like the other great masters of his time, he gave priority to creativity. He worked with new techniques, such as the use of canvas as a pictorial support and oil painting. He also dealt with new themes, not only the omnipresent religious painting, but also portraits and the representation of Nature. He has a very particular pictorial style and is therefore easy to identify. In his work converge the geometric perspective of Brunelleschiana, the plasticity of Masaccio, the soaring light that lightens the shadows and soaks the colors of Fra Angelico and Domenico Veneziano, as well as the precise and attentive description against the reality of the Flemish. Other fundamental characteristics of his poetic expression are the geometric simplification of both composition and volumes, the ceremonial immobility of gestures, the attention to human truth.

His works are admirably balanced between art, geometry and a complex system of reading at many levels, where complex theological, philosophical and topical issues come together. He managed to harmonize, both in his life and in his works, the intellectual and spiritual values of his time, condensing multiple influences and mediating between tradition and modernity, between religiosity and the new affirmations of Humanism, between rationality and aesthetics.

His activity can be characterized as a process that goes from pictorial practice to mathematics and abstract speculation. His artistic production, characterized by the extreme rigor of the perspectival research, the monumentality of the figures, the expressive use of light, influenced the deep Renaissance painting of northern Italy and, in particular, the Ferrarese and Venetian school.

His work is characterized by a classical dignity, similar to Masaccio. The term that best defines his art is "tranquility", which does not prevent it from having a rigorous technical treatment. One can also perceive the desire to construct a rational and coherent space. Piero was very interested in the problems of chiaroscuro and perspective, like his contemporary Melozzo da Forli. Piero della Francesca and Melozzo da Forlì are the most famous masters of perspective in the 15th century, recognized as such by Giorgio Vasari and Luca Pacioli. He stands out for his knowledge of perspective and composition, which was influenced by his mathematical knowledge, merging art with the science of mathematics, geometry and perspective. Linear perspective was his main characteristic when painting, which can be seen in all his paintings, which are basically distinguished by their luminous colors and a soft but firm line in the figures. His compositions are clear, balanced, reflecting with mathematical precision the architectures. Without yielding to trompe l'oeil effects, Piero used perspective in order to plan grandiose naturalistic compositions.

In these serene landscapes he introduced the figures of the characters with a very volumetric treatment: an anatomical study is perceived, and a certain monumentality. However, they are very static characters, who remain as if frozen and suspended in their own movements, resulting a bit cold, inexpressive, monolithic. This absence of nervousness is the opposite of the rest of the Florentine Renaissance painters, who, as time went on, made increasingly dynamic figures. Roberto Longhi, when speaking of Piero della Francesca, says that his figures are "columns". The treatment of the figures in simple volumes expresses a feeling of timelessness, as does the harmony of the light tones; all this expresses the poetic sense of Piero della Francesca's art.

The atmospheric light is another of his outstanding features, which he acquired from his master Domenico Veneziano, and which he used to symbolize the perfection of divine Creation. It is very diaphanous, very diurnal, with a uniform treatment, without intensities or light gradation (slightly archaic, similar to that of Fra Angelico). His essays in this sense come to give the sensation that his figures are modeled in material endowed with its own light, intimate, radiant. Frescoes such as the Legend of the Holy Cross, in the apse of the Church of San Francesco in Arezzo, are a work of art in luminosity.

List of his works (panel paintings and frescoes) in chronological order.

Workshop works

Bohuslav Martinů wrote a work in three movements for large orchestra entitled Les Fresques de Piero della Francesca, H. 352 (1955). Dedicated to Rafael Kubelik, the latter premiered it, together with the Vienna Philharmonic at the 1956 Salzburg Festival.

The singer-songwriter Javier Krahe dedicated a satirical song titled Piero Della Francesca to him in his 2002 album Cábalas y Cicatrices. In the presentation of the song he used to make a brief summary of the painter's life highlighting his facet as a geometrician.

Sources

1. Piero della Francesca
2. Piero della Francesca
3. a b c Turner, A. Richard (1976). «Piero della Francesca». En William D. Halsey, ed. Collier's Encyclopedia 19. New York: Macmillan Educational Corporation. p. 40–42.
4. Dominique Christian, Art de diriger & art de peindre : études comparées de l'invention de la perspective à la Renaissance et de la prospective stratégique aujourd'hui, Ed. DIFER, 1er janvier 1997, 135 p. (ISBN 978-2-9511826-0-8, lire en ligne), p. 67
5. (en) James R. Banker, « Piero della Francesca's S. Agostino Alterpiece : some new documents », The Burlington Magazine, vol. 129,‎ 1987, p. 645-651.
6. ^ a b Luca Pacioli, Summa de Aritmetica, geometria, Proportioni et Proportionalità, Paganino Paganini, Venezia, 10 novembre 1494, p. 68.«Pacioli cita Piero della Francesca nella Summa una prima volta nell’epistola dedicatoria dove ne parla al presente, ma successivamente precisa: El sublime pictore (al dì nostri ancor vivente) maestro Pietro de li Franceschi nostro conterraneo del Borgo San Sepolcro. In merito alla data di nascita, va evidenziato che Roberto Longhi e Eugenio Battisti, hanno ipotizzato una data compresa tra il 1420 e il 1422, se ciò fosse vero, tenendo conto che il Vasari afferma che Piero morì all'età di 86 anni, dobbiamo dedurre che la sua data di morte sia intorno a1506/1508 e pertanto ancora vivente nel 1494, come scritto da Luca Pacioli.»
7. ^ According to Giorgio Vasari, Piero would have worked for Federico's father Guidantonio, who died in February 1443. However, this is unlikely because this statement is not confirmed by documents or paintings. Vasari may have confused Guidantonio with Federico.
8. ^ Although he may have given up painting in his later years, Vasari's remarks that he went blind at the age of 60 have to be doubted,[14] since he completed his 1485 treatise on regular solids in his own handwriting.
9. ^ Dedicated to Guidobaldo da Montefeltro, son and heir of Duke Federico