 Leonardo had no income during the spring of 1503 , which may in part explain his interest in a private portrait . But later that year , he most likely had to delay his work on Mona Lisa when he received payment for starting The Battle of Anghiari , which was a more valuable commission and one he was contracted to complete by February 1505 . In 1506 Leonardo considered the portrait unfinished . He was not paid for the work and did not deliver it to his client . The artist 's paintings traveled with him throughout his life , and he may have completed Mona Lisa many years later in France , in one estimation by 1516 . 
