Raffaello Sanzio da Urbino
In 1508, at the age of 25, he was called to the court of Pope Julius II to help with the redecoration of the papal apartments. In Rome he evolved as a portraitist, and became one of the greatest of all history painters.
He remained in Rome for the rest of his life and in 1514, on the death of Bramante, he was appointed architect in charge of St Peter's.
[Biography from The National Gallery.]