The temple of Venus was built in the third century. It has a highly original design: built on a horseshoe-shaped platform, it consists of a circular shrine with a square entrance that is almost as big. The outer façade of the shrine is graced by five niches, which means that there is not a single square wall. In the niches are representations of doves and shells, which has been taken as evidence that the shrine was dedicated to Venus.
The square entrance probably was not one of those classical triangle-shaped pediments supported by columns. In fact, the straight horizontal line was broken by an elegant arch. This is certainly not without parallel, but the baroque ensemble suggests that the architect wanted to show off that he was the best and the brightest. He succeeded.
The temple was later used as a church, dedicated to Saint Barbara. According to the (comparatively late) Christian legend, she was the daughter of a Heliopolitan dignitary, Dioscorus, who still worshipped the old gods.