Great architect and theoretician of art, the natural son of a Florentine exiled to Genoa, Alberti exerted a significant influence on Leonardo's scientific and technological knowledge. Leonardo could find a reflection of Albert's ideas on perspective and structure in the numerous buildings erected by the famous architect in Florence: the Loggia and Palazzo Rucellai in Via della Vigna Nuova, begun in 1447, the façade of Santa Maria Novella from 1456, the tempietto of the Holy Sepulchre in San Pancrazio (1467), and the dome of the Santissima Annunziata (1470). Well known to Leonardo, as to other Renaissance men of learning, were Alberti's theoretical works, such as his De Statua [Concerning statues], De pictura [Concerning painting] and De re aedificatoria [Concerning buildings]. These writings are, in fact, recurrently mentioned in Leonardo's notes (Codex Atlanticus, Codex Arundel, Madrid Ms. II and Codex Leicester), in which he re-elaborates and discusses theories and technical solutions proposed by Alberti.

Mathematician, author of a treatise on abacus and of a Pratica di Aritmetica [Exercises in arithmetic] known as «maestro Benedetto», he also held the position of procurator of the monastery of Santa Maria degli Angeli. His name recurs several times in the deeds notarised by Ser Piero, Leonardo's father, around 1476 (documents now in the Florence State Archive). He is mentioned by Leonardo as «Benedetto of the abacus». This definition might indicate that Benedetto could have been Leonardo's master of abacus, who was instead, according to other hypotheses, Giovanni del Sodo, another Florentine mathematician mentioned in the Codex Arundel and the Codex Atlanticus.

Painter of masterpieces such as those now displayed in the Uffizi Gallery in Florence (the Primavera, the Venus, the Pallas, the Calumny, the Mystic Nativity, the Judith, the Madonna del Magnificat, among others), Botticelli was a pupil of Verrocchio along with Leonardo. He is recalled in the Codex Atlanticus in friendly but argumentative tones, and again in the Book on Painting in a passage where Leonardo criticizes his landscapes: «This painter made very sad landscapes».

Noteworthy is the presence in Florence of the fresco of St . Augustine in his studio, in which appears an astrolabe that recalls the drawing of a perspectograph done by Leonardo around 1480. Botticelli painted this fresco around the same date, 1480, in the Church of Ognissanti, where he was later to be buried.

This towering figure of the Early Renaissance was a sculptor (the Sacrifice of Isaac for the Baptistery, now in the Bargello; the Crucifix in the Gondi Chapel in Santa Maria Novella) and architect in Florence. Among his masterpieces we may admire today the dome over Santa Maria del Fiore, the Hospital of the Innocenti, the Church of Santo Spirito, the Church and Sacristy of San Lorenzo, and the Pazzi Chapel.

Also attributed monuments to him are buildings scattered among the towns of Signa, Malmantile and Vicopisano, which could constitute the interesting stages of an itinerary that is only apparently a "minor" one.

Brunelleschi exerted notable influence on Leonardo, who re-elaborated his construction site machines in the Codex Atlanticus.

Thanks to a folio of the Leonardesque school (now in the Uffizi, Cabinet of Drawings and Prints) the projects for a river boat called the "Badalone" and for a self-propelled wagon invented by Brunelleschi, of whom no autograph drawings have hitherto been found, are known to us. Lastly, Brunelleschi was indirectly Leonardo's master in perspective and probably, through their mutual friend Paolo dal Pozzo Toscanelli, in his mathematical concepts.

Author of some famous masterpieces such as the Maestà in the Uffizi, the Crucifix in Santa Croce, and the mosaics in the Baptistery, on which he collaborated, Cimabue is mentioned by Leonardo as Giotto's master.

Born in Florence, of a family coming from Monteboro, a locality not far from Empoli, he was in Rome with Leonardo when he was assigned by Pope Leo X Medici to take a message to Ethiopia. He left by ship from Portugal, and, upon reaching India wrote to Giuliano de’ Medici. The letter, dated January 6, 1515 according to the Florentine calendar (1516), contains an ambiguous mention of Leonardo, which has given rise to his fame as a "vegetarian" and "animalist": «Where the river Indo flows into the sea it is inhabited by people called Guzaratti… They do not eat anything that contains blood, and do not let anyone among them harm any living thing, like our own Leonardo da Vinci. They live on rice, milk and other inanimate foods [...]» (documented in a section of the Ideal Museum at Vinci).

Andrea Corsali is also mentioned in the De Subtilitate by Girolamo Cardano (1501-1576), son of the mathematician Fazio, a friend of Leonardo's.

He conducted important astronomical and geographic investigations; corrected Ptolemy's error on the longitude between the African coast and that of India; was the first to discover the existence of New Guinea; distinguished Sumatra from Ceylon and furnished an exact description of the customs and habits of the peoples he encountered in his voyages. From historical sources we know that he introduced movable type for printing into Africa. His fame in the field of astronomy derives from his first description of the Southern Cross and the "Clouds of Magellan", later attributed to Antonio Pigafetta (who in reality noted them only four years later).

The dynasty of artists that included Luca (1400-1482), his nephew Andrea (1435-1528), and Andrea's son Giovanni (1469-1529); among their assistants were Benedetto (1461-1521) and Santi Buglioni (1494-1576).

Their shop is accredited with the "invention" of glazed terracotta, the technique applied in a vast number of works for the churches and buildings of Florence and Tuscany as a whole (from the Pazzi Chapel to the Sanctuary of La Verna), found today in the most important museums of the Region, from the Museum of Cathedral Works to that of the Bargello.

Leonardo mentions them in his Book on Painting: «They who found a way to transpose every great pictorial work onto terracotta covered with glaze».

Florentine family of clockmakers, goldsmiths, astronomers, mathematicians, inventors and cartographers whose members included Lorenzo (1446-1512), Bernardo (c. 1475-1522), Camillo (1484-1560), Benvenuto (1486-1532), Eufrosino (late 15th – 16th century) and Girolamo (c. 1530-1614).

In January 1504 Lorenzo was with Leonardo among the experts consulted on where to place Michelangelo's David. It is highly probably that Lorenzo and Leonardo exchanged their experience on the subject of clock-making and other technological studies.

In Venice, at the Marciana Library, is the manuscript of «Benvenuto di Lorenzo di Benvenuto della Golpaia composed and illustrated by his hand with many beautiful inventions and their bases», in which are found notes on technologies and inventions attributable to Leonardo: «Copy of an instrument sent by Lionardo da Vinci to Bernardo Ruciellai of France, made by a countryman from Domodossola, the drawing of which appears here» (7v); in addition to the method for dividing a line into equal parts (39r); and into "sixths" (49v).

In Florence, at the Medici Laurentian Library, is the Antinori Manuscript ("Della Golpaia Girolamo, Benedetto, Benvenuto and Lorenzo: Studies in clock-making, mechanics, and astronomy, with pertinent figures and explanations from the 16th century"), while in the National Central Library are the Magliabechian manuscripts, such as the one "Copied by j libriccino by the hand of Lorenzo our father" and compiled by Eufrosino, with the project for the planetary clock.

In the Museum of the History of Science in Florence are displayed the nocturnal clock signed and dated "Laurentius Vulparia Florentinus 1511", a quadrant with sundials on a plate by Camillo di Lorenzo, a compass in the shape of a dagger by Benvenuto di Lorenzo, two armillary spheres, two nocturnal clocks, a sundial a solar quadrant and two sundials by Girolamo di Camillo.

In the Codex Atlanticus, Leonardo mentions this painter, famous above all for the great panel of Dante and the Divine Comedy in Santa Maria del Fiore, who also painted the delightful Madonna in the Bigallo Museum.

Architect and engineer; in 1458 the initial project for Palazzo Pitti was commissioned of him in Florence. He also collaborated with Alberti in Mantua for the Gonzaga dukes, while in 1487 he was in Milan, where he met Leonardo.

Fancelli had been summoned to that city to judge the projects for the lantern over the Milan Cathedral, on which Leonardo too was working. And it was from Milan that Fancelli wrote on August 12, 1487, in agreement with the ambassador of Florence Pietro Alamanni, to Lorenzo the Magnificent, describing a project destined to make the Arno navigable from Florence (Mulina d’Ognissanti) to Signa, following the natural course of the river. From the words of Vasari and the descriptions of Fancelli it can be seen that this was not a question of creating an alternative course for the river, but rather of «putting it in a canal». Fancelli's daughter Chiara married Perugino.

The son of Filippo and pupil of Botticelli, he was enrolled in the Company of San Luca in 1472, as was Leonardo, and was a close friend of his, as shown by their exchanges of commissions for paintings.

In 1478 Leonardo was commissioned to paint the altarpiece for the Chapel of San Bernardo in Palazzo della Signoria, which had originally been commissioned of Piero del Pollaiolo. Leonardo failed to complete the work, although he had done a cartoon that, after being temporarily assigned to Ghirlandaio, was used by Filippino to finish the work in 1485.

In 1501 Lippi left to him the task of painting an altarpiece of Saint Anne for the high altar of Santissima Annunziata, a work that Leonardo undertook but failed to finish.

Ugolino Verino (1438-1516) jokingly hailed Filippino and Leonardo as the «new Apelles and the new Protogenes» (the latter recalled chiefly for his proverbial slowness in completing a painting).

Among his major works in Florence are: the Apparition of the Virgin to St. Bernard (in the Badia Fiorentina), the frescoes in the Brancacci Chapel at the church of the Carmine (along with those of Masaccio), the Virgin and Saints and the Adoration in the Uffizi, and the frescoes in the Strozzi Chapel in Santa Maria Novella. His Annunciation is now in the Museum of Gimignano.

Born in Siena, he was an architect, engineer, painter and sculptor. His pictorial masterpieces, such as the Coronation (1472) and the Nativity (1475), are now in the Pinacoteca of Siena.

Leonardo studied his treatises (marginal notes in the Ashburnam Ms. in the Laurentian Library in Florence, and passages copied in Madrid Ms. II, during his time in Piombino) and was with him at Pavia in 1490.

Some of Leonardo's autograph drawings, including that of the "Etruscan mausoleum", now in the Louvre, were attributed to him in the past.

Recent attempts have been made to assign Leonardo a very important role, although not yet proven, in Francesco di Giorgio's architectural works, such as Santa Maria delle Grazie at Cortona. It is more probable instead that Leonardo was influenced by him.

A painter, like his brothers David and Benedetto, he was the master of Michelangelo. His son Ridolfo was to be a disciple of Fra Bartolomeo.

He is considered to be, like Leonardo, one of Verrocchio's pupils. To him were once attributed two masterpieces, the Annunciation in the Uffizi, today attributed by most critics to Leonardo, and a singular painting, the Miller Tondo in Palazzo Vecchio, coming from the circle of Verrocchio, Leonardo and Cosimo Rosselli.

In Florence his major works are found in the churches of Santa Trinita and Santa Maria Novella; in the latter church, in the Portrait of a Lady in the Tornabuoni Chapel, painted prior to 1490, he foreshadows the dynamic pose of the Mona Lisa. Other masterpieces by him are found in the Uffizi Gallery (such as the Adoration and the Portrait of Giovanna Tornabuoni) and in Palazzo Vecchio (Allegory of Florence). Noteworthy are his Last Suppers in the Refectory of Ognissanti and the San Marco Monastery (another of his Last Suppers is found in the Badia a Passignano). Nor should we forget the Episodes from the life of Santa Fina in the Collegiate of San Gimignano.

In January 1504 he too was, with Leonardo, one of the experts consulted on where to place Michelangelo's David.

The great painter, architect and sculptor, born at Vicchio nel Mugello, is recalled by Leonardo with admiration around 1490 in the Codex Atlanticus for having resurrected the art of painting from decadence and imitation, starting from a study of nature.

In 1334 Giotto was magister of the Opera di Santa Reparata (the Cathedral works) and architect of the fortified walls around Florence. In this city, among the works and architectural achievements attributable to him, we can admire the Bell Tower of the Cathedral, the cycle of frescoes in Santa Croce, and the Maestà in the Uffizi.

Painter, «goldsmith outstanding in his time», as wrote Vasari, he was above all a pupil of Verrocchio (who named him his heir) and a disciple of Leonardo, with whom he had many points in common as regards pictorial style. This is shown by the fact that the Ginevra Benci and the Lady with an Ermine, masterpieces of Leonardian portrait painting, were once attributed to Lorenzo.

In the Uffizi are some of his youthful masterpieces such as the Annunciation and the Venus. At San Domenico di Fiesole can be seen the Baptism of Christ, inspired by that of Verrocchio and Leonardo now in the Uffizi. In the Cathedral of Pistoia is the great altarpiece of the Piazza Madonna, attributed to him, although commissioned of Verrocchio. In this work, some have hypothesised the participation of Leonardo.

A friend of Leonardo at the time when he was Secretary of the Florentine Republic.

They were in close contact during the early years of the 16th century, when Leonardo was in the service of Cesare Borgia, working on the project for deviating the Arno around Pisa as well as on the fortifications of Piombino, and had begun to paint the Battle of Anghiari.

Machiavelli was assigned important missions up to time of the Medici's return to Florence, in 1512. Dismissed from service, he retired to the Villa dell’Albergaccio at Sant’Andrea in Percussina, a village near San Casciano, where he wrote his fundamental political works (The Prince, the Art of Warfare) and theatrical works (La Mandragola, La Clizia). Before his death he returned to hold public office again thanks to the historian Guicciardini and to Pope Clement VII, who offered him the position of director of works for the fortification of the Florentine walls.

The brother of another painter known as Scheggia, Massacio was born at San Giovanni Valdarno and lived in Florence in the Popolo di San Niccolò Oltrarno.

He brought extraordinary innovations to early fifteenth-century Florentine art, first among them perspective. His work was studied and admired by Leonardo, who in the Codex Atlanticus (around 1490) praised him as the painter who showed «with perfect work how those who took for author anything other than nature, the master of masters, laboured in vain».

In Florence can be seen his frescoes in the Brancacci Chapel in Santa Maria del Carmine, the Trinity in Santa Maria Novella, and the Saint Anne Metterza formerly in the church of Sant’Ambrogio, now in the Uffizi. Notable is the Triptych of San Giovenale representing the Virgin and Child Enthroned with two Angels in the Pieve di San Pietro a Cascia, near Reggello.

A native of Borgo Sansepolcro. In 1500 Leonardo returned to Florence accompanied by Luca Pacioli, who stayed as guest in the Franciscan monastery of Santa Croce. Leonardo had met the illustrious mathematician in Milan, where he had been his pupil during the years when he was illustrating the De Divina Proportione. Of this work, finished in 1498, three manuscript copies were compiled: the first is now in the Geneva Civic Library, the second in the Milan Ambrosian Library, and the third has been lost.

Pacioli recalled, among other things, in the De Viribus Quantitis, a manuscript from 1496 now at the University of Bologna Library, an emergency bridge made by Leonardo, "noble engineer of Cesare Borgia, Duke of Romagna and Lord of Piombino", without «either iron bars or ropes», to allow an army to cross a river.

Painter, inspired by Piero della Francesca, he worked in Verrocchio's shop alongside Leonardo. Raphael's father, Giovanni Santi, described them in his poem, written in honour of Federico da Montefeltro around 1485, as «two youths equal in estate and in love».

In 1493 he married Chiara, the daughter of Luca Fancelli da Settignano.

Numerous works of his remain in Florence, among them the Last Supper in the Monastery of Sant’Onofrio, or of Fuligno, rediscovered in the 19th century and initially attributed to Raphael, the fresco of the Crucifixion in Santa Maria Maddalena de’ Pazzi, as well as paintings now in the Palatine Gallery of Palazzo Pitti and in the Uffizi.

It has been suggested that Leonardo may have participated, in the landscape at least, in Perugino's Virgin with two Angels now at the National Gallery in London,.

The great artist from Borgo Sansepolcro is explicitly mentioned by Leonardo as «Maestro Piero del Borgo» among his bibliographical sources for the De Prospectiva pingendi. Leonardo was undoubtedly influenced by the painting and mathematical concepts of Piero, whose work was known to him through the cycles of frescoes and panel paintings.

In Tuscany, the Piero's works can be seen in Florence at the Uffizi, in Arezzo at the church of San Francesco, at Monterchi and in the Museum of Sansepolcro.

Famous for the art of cooking, Platina was born at Piadena, near Cremona. He frequented the courts of the Gonzaga and the Medici, was prefect of the Vatican Library and in close contact with the Medicean Academy of Careggi, along with Ficino.

Leonardo mentions him three times, in particular for his De honesta voluttà [Concerning honest pleasure] (published in 1487): «as wrote Platina and the other authors of gastronomy».

Antonio Benci (1431 -1498) and Piero Benci (1441 c.-1496), known together as the Pollaiolo.

Both were painters: Antonio, more than his brother, excelled in the goldsmith's art and in sculpture as well. His masterpieces of goldwork are found in the Museum of Cathedral Works, while in the Bargello Museum are the Bust of a Warrior and the Hercules and Anteus forming part of the lost Labours of Hercules accomplished for Piero de’ Medici around 1460, of which an echo may be found in one of the two small panels in the Uffizi. He was one of the first great engravers (as exemplified by the extraordinary Battle of the Nudes).

Undoubtedly, he strongly influenced the young Leonardo, as regards both style and the study of anatomy. Equally evident are the links as regards landscape and the intense dynamics of figures in space.

At Staggia di Poggibonsi is the Communion of St. Mary Magdalene transported to Heaven by the Angels, painted by Antonio while he was working in the nearby town of San Gimignano.

Of Piero, the panels of The Virtues commissioned by the Florentine Guilds in 1469 are displayed in the Uffizi,

In his youth he was a pupil of Leonardo. He came from Pontorme, a village near the Arno river not far from Empoli and only 10 kilometers from Vinci, represented by Leonardo on his maps. At Pontorme are found today the Saints painted by him in the Church of San Michele, while the house where he was born has been restored and is open to the public.

Among his many works visible in Florence are the Deposition in the Church of Santa Felicita, the frescoes in the Santissima Annunziata and the Certosa del Galluzzo, the Pucci Altarpiece in San Michele Visdomini, the frescoes of the Tabernacle of Boldrone in the Academy of the Art of Drawing, the panel paintings in the Palatine Gallery and the Uffizi. Among his works found outside of Florence, the most famous are the fresco of Vertumnus and Pomona in the Medicean Villa of Poggio a Caiano, the Visitation in the Church of San Michele at Carmignano, the St. Quentin in the Sansepolcro Museum, and the Portrait of a Youth in the Pinacoteca of Palazzo Mansi at Lucca.

A sculptor who trained as a young man with Verrocchio's circle, he was influenced by Leonardo, as shown by some roughed-out sculptures inspired by the Battle of Anghiari.

His family lived in a house adorned with the heraldic arms of the griffon, between Via dei Neri and Piazza Peruzzi, in today's Via dei Rustici.

Starting in 1506 he worked on the sculptural group representing the Preaching of the Baptist for the Florentine Baptistery, with the advice and perhaps the participation of Leonardo; the two artists lived together in the nearby Palazzo Martelli.

In Florence his works can be seen at the Bargello Museum, among other places.

At Certaldo, his Bust of Boccaccio is found in the Church of Santi Jacopo e Filippo.

Antonio Giamberti, known as Antonio da Sangallo the Elder (1455 c.-1534)

In Tuscany he worked as architect in Poggibonsi, Arezzo, Livorno, Florence, and especially Montepulciano, where he built the Church of the Madonna di San Biagio in the shape of a Greek cross as well as several palaces.

Almost certainly his are some annotations in Leonardo's Madrid Ms. II, dating from the years when they were working together at Piombino.

Giuliano Giamberti, known as Giuliano da Sangallo (middle of the 15th century-1516)

Architect, military engineer and sculptor. He was with Leonardo in Milan in October 1492 to present Ludovico Sforza with the project for a grandiose palace.

In Florence he worked on the cloister of Santa Maria Maddalena de’ Pazzi, the sacristy of Santo Spirito and Palazzo Gondi, the latter linked to memories of Leonardo's family. He also worked on the fortifications of Colle Valdelsa, Poggibonsi, Sansepolcro and Arezzo. Lastly, he designed the Medicean Villa at Poggio a Caiano and, starting from 1484, worked on the church of Santa Maria delle Carceri in Prato. This building, with its Greek-cross central plan, constituted a model for the religious architecture of the Renaissance.

Antonio Cordini, known as Antonio da Sangallo the Younger (1483/85-1546)

Architect and wood carver, he worked in Rome in Bramante's circle and collaborated with Raphael.

At Orvieto he designed the Pozzo of San Patrizio, which has a forerunner in Leonardo's drawing of a "double winding" stairway found in Ms. B (c. 1487).

Sculptor, goldsmith and painter. The presence of Leonardo in his shop is expressly documented in the records of the trial for sodomy that took place in 1476 («he stays with Andrea del Verrocchio»). That Leonardo belonged to Verrocchio's school is also confirmed by other sources and is clearly demonstrable on the basis of stylistic elements in such works as the Annunciation and the Baptism in the Uffizi.

Verrocchio's first workshop, in the years around 1470, was probably located in his house on the corner of Via dell’Agnolo and "Via Pentolini sive Malborghetto" (today's Via de’ Macci). Later, he «kept a pension with several rooms» in another quarter, behind the Cathedral, where some years earlier had been the shop of Michelozzo and Donatello, the latter of whom had profoundly influenced him.

In 1472, in the presence of the young Leonardo, Verrocchio managed to hoist the copper sphere to the top of the lantern over the dome of Santa Maria del Fiore.

Famous among Verrocchio's sculptures now in Florence are: the David and the Lady with a Bunch of Flowers, now in the Bargello Museum, the Incredulity of St. Thomas for Orsanmichele, the Putto with a Dolphin on the fountain at the centre of the courtyard of Palazzo Vecchio and lastly, the Sepulchre of Piero and Giovanni de’ Medici in the Old Sacristy of San Lorenzo. It has been hypothesized by some art historians that Leonardo collaborated on these works.