He was probably a pupil of Fra Fillipo Lippi, and was influenced by followers of Paulo Polliauolo, especially around 1470 when he painted Fortitude, to complete a set of seven paintings themed on the seven virtues (the other six paintings were all by Polliauolo).
His painting style, like that of many Florentine artists of the period, depends on outline for its emotional expression, but he seems also to have chosen a deliberately out-of-date style.
His great masterpieces - The Birth of Venus and Primavera are striking in their originality of composition and study. They now rank amongst the greatest works of art. 
The Birth of Venus and Primavera were both ordered by the Medici family, who ruled Florence, but by 1480 Botticelli was in Rome, painting frescoes in the Sistine Chapel, but these do not seem to have been successful. From this time he made a good living painting large numbers of Madonnas.