section_path: Biography/First Florentine period (1472–c. 1482)
section_name: First Florentine period (1472–c. 1482)
paragraph_text: First Florentine period (1472–c. 1482)
  
  By 1472, at the age of 20, Leonardo qualified as a master in the Guild of Saint Luke, the guild of artists and doctors of medicine, but even after his father set him up in his own workshop, his attachment to Verrocchio was such that he continued to collaborate and live with him. Leonardo's earliest known dated work is a 1473 pen-and-ink drawing of the Arno valley (see below). According to Vasari, the young Leonardo was the first to suggest making the Arno river a navigable channel between Florence and Pisa.
  
  In January 1478, Leonardo received an independent commission to paint an altarpiece for the Chapel of Saint Bernard in the Palazzo Vecchio, an indication of his independence from Verrocchio's studio. An anonymous early biographer, known as Anonimo Gaddiano, claims that in 1480 Leonardo was living with the Medici and often worked in the garden of the Piazza San Marco, Florence, where a Neoplatonic academy of artists, poets and philosophers organised by the Medici met. In March 1481, he received a commission from the monks of San Donato in Scopeto for The Adoration of the Magi. Neither of these initial commissions were completed, being abandoned when Leonardo went to offer his services to Duke of Milan Ludovico Sforza. Leonardo wrote Sforza a letter which described the diverse things that he could achieve in the fields of engineering and weapon design, and mentioned that he could paint. He brought with him a silver string instrument – either a lute or lyre – in the form of a horse's head.
  
  With Alberti, Leonardo visited the home of the Medici and through them came to know the older Humanist philosophers of whom Marsiglio Ficino, proponent of Neoplatonism; Cristoforo Landino, writer of commentaries on Classical writings, and John Argyropoulos, teacher of Greek and translator of Aristotle were the foremost. Also associated with the Platonic Academy of the Medici was Leonardo's contemporary, the brilliant young poet and philosopher Pico della Mirandola. In 1482, Leonardo was sent as an ambassador by Lorenzo de' Medici to Ludovico il Moro, who ruled Milan between 1479 and 1499.