The Battle of Anghiari (Leonardo da Vinci)
In 1504 Leonardo da Vinci was given the commission by gonfaloniere Piero Soderini, a contract signed by Niccolò Machiavelli, to decorate the Hall of Five Hundred. At the same time his rival Michelangelo, who had just finished his "David", was designated the opposite wall. This was the only time that Leonardo da Vinci and Michelangelo worked together on the same project. The painting of Michelangelo depicted an episode from the Battle of Cascina, when a group of bathing soldiers was surprised by the enemy. However Michelangelo did not stay in Florence long enough to complete the project. He was able to finish his cartoon, but only began the painting. He was invited back to Rome in 1505 by the newly appointed Pope Julius II and was commissioned to build the Pope's tomb.
David with the Head of Goliath (Caravaggio, Vienna)
The model for David in both versions appears to be a more mature version of the pubescent Cupid of "Amor Vincit Omnia" and the Capitoline and Pamphilij "John the Baptist", all painted around 1602. The model for these works has been identified by some, most notably Peter Robb, as Cecco, a boy known to have been Caravaggio's servant in Rome in the early 17th century and believed by Robb to be identical with Cecco del Caravaggio, an artist active in Rome in the period 1610–1625 and painting very much in Caravaggio's manner. There is no record of Cecco having been with Caravaggio after the artist's flight from Rome in 1606.