It was commissioned 1501 and completed in 1510-11. I found that there are conflicting stories of the patron or/ patrons and date of commission. Some state that it was Pope Julius II in 1501 while others sources state it was Ferdinand and Isabel of Spain in 1502.

While the Tempietto stood 13 meters high, the dome of St. Peter's rises to a 120 meters. This is a drastic difference.