In 1466, at the age of fourteen, Leonardo was apprenticed to one of the most successful artists of his day, Andrea di Cione, known as Verrocchio.
Leonardo would have been exposed to a vast range of technical skills and had the opportunity to learn drafting, chemistry, metallurgy, metal working,
By 1472, at the age of twenty, Leonardo qualified as a master in the Guild of St 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 with him. Leonardo's earliest known dated work is a drawing in pen and ink of the Arno valley, drawn on 5 August 1473.