Jupiter is the god of light and sky and protector of the state and its laws. He is referred to as the supreme god. He is a son of Saturn and brother of Neptune and Juno (who is also his wife). The Romans worshipped him especially as Jupiter Optimus Maximus. He had a temple on the Capital, together with Juno and Minerva. His temple was not only the most important sanctuary in Rome, it was also the center of political life. Here official offerings were made, treaties were signed and wars were declared. The Ides of each month (13 or 15) and the full moon were sacred to Jupiter.

• He was worshipped at the festival of the Vinalia of August 19, which was shared with Venus