It was the year 1504 in Florence, and Leonardo da Vinci was very busy. He used to travel around Italy from court to court to work as an artist and engineer, often returning to his hometown, Florence, for short but very productive periods. He had just abandoned the large wall painting of the Battle of Anghiari in Palazzo Vecchio, after a disastrous attempt to reproduce the ancient (and lost) Roman technique of encaustic. Also, he had already started painting his most famous painting ever, the Mona Lisa.