Portrait of Pope Julius II, Raphael, 1512
In February Leonardo possibly ends his service for Cesare Borgia and returns to Florence. In July he is re-inscribed in the account book of the painters’ confraternity.
In July Leonardo is officially being paid by the Signoria of Florence in connection with Machiavelli's scheme to redirect the Arno at Pisa. Although the work is begun to divert the flow of the river into two canals, the scheme ultimately fails.
On 24th October Leonardo receives the key to the Sala del Papa, (the "Hall of the Pope") in the church of Santa Maria Novella, Florence, to use as a workshop in which to execute the cartoon for the Battle of Anghiari fresco commissioned by the government of Florence.
Leonardo may have begun the Mona Lisa during this year and finished it some time later, possibly working on it over a period of many years.
Paris Manuscript K is begun.
Pope Alexander VI dies. Cesare Borgia flees to Spain. Guiliano della Rovere is elected Pope Julius II.