The Temple of Jupiter, also known as ‘Roman Heliopolis’, was a holy complex dedicated to the belief of Zeus in Heliopolis of Roman Phoenicia, which is now known as Baalbeck in Lebanon. The sanctuary can be reached by an impressive stairway and is considered to be one of the largest temples of the Roman world, measuring approximately 88 x 48 meters. Although there are only six columns remaining today, each about twenty meters high and two meters wide, they give a clear idea of the original enormous size of the temple. It is believed that the Temple of Jupiter was constructed on top of an earlier Phoenician temple, using the same infrastructure and foundation.
Situated at an altitude of about 1100 meters on the east side of the Roman Empire, the construction of the temple was completed in several stages. Although it was almost finished during Nero's reign (54-68 AD), it was not inaugurated until the 3rd century, along with the other two temples. During the Byzantine era, it was referred to as the ‘Trilithon’ because of the three gigantic stones in its foundation and called the ‘Great Temple’ when taken together with the forecourt and Great Court.