Raphael
Raphael was enormously productive, running an unusually large workshop and, despite his death at 37, leaving a large body of work. Many of his works are found in the Vatican Palace, where the frescoed Raphael Rooms were the central, and the largest, work of his career. The best known work is "The School of Athens" in the Vatican Stanza della Segnatura. After his early years in Rome much of his work was executed by his workshop from his drawings, with considerable loss of quality. He was extremely influential in his lifetime, though outside Rome his work was mostly known from his collaborative printmaking.
Timoteo Viti
In 1503 Viti was painting banners for Cesare Borgia, who had expelled Duke Guidobaldo da Montefeltro as lord of the city. Guidobaldo regained Urbino in 1504 and Viti, along with Girolamo Genga, was commissioned by Bishop Arrivabene to decorate the chapel of S Martino in the cathedral. He continued to work successfully in the Marches for the rest of the decade, and as far south as Siena, where he and Genga collaborated on paintings in the Palazzo Petrucci in about 1508. 
Around 1514, Viti formed part of the large team assembled by Raphael and worked on the frescoes Raphael designed in the Chigi Chapel in Santa Maria della Pace in Rome. It has been suggested that he is depicted (as the Ancient Greek painter Protogenes) in "The School of Athens", Raphael's most famous work, standing next to Raphael's self-portrait, although Vasari does not mention this identification.