When Was the Mona Lisa painted?
According to Wikipedia
Leonardo da Vinci began painting the Mona Lisa in 1503 or 1504 in Florence, Italy. Although the Louvre states that it was “doubtless painted between 1503 and 1506”, the art historian Martin Kemp says there is some difficulty in confirming the actual dates with certainty. According to Leonardo’s contemporary, Giorgio Vasari, “after he had lingered over it four years, [he] left it unfinished”. Leonardo, later in his life, is said to have regretted “never having completed a single work”.
In 1516, Leonardo was invited by King François I to work at the Clos Lucé near the king’s castle in Amboise. It is believed that he took the Mona Lisa with him and continued to work after he moved to France. Art historian Carmen C. Bambach has concluded that da Vinci probably continued refining the work until 1516 or 1517.
Source: Arts Cosmos