Baalbek Heliopolis was built on the original site of the temples of the Phoenician goddess Astarte (the goddess of war and sexual love) and the Canaanite god Ba’al (the god of fertility, weather and war). During the Roman rule (64 BC–646 AD), the complex was rebuilt, trading Astarte for Venus and Ba’al for Jupiter.  The construction of the temple of Jupiter (god of the gods) began in 16BC and completed in 60AD; the construction of the Temple of Bacchus (god of wine) and the Temple of Venus (goddess of love, beauty, desire, fertility and prosperity) followed.  The Temple of Venus was built a the site of the Temple of Muses, dating back to the first century AD. 

In 313 AD when Christianity was declared the offical religion of the Roman Empire, the Emperor of Byzantine (now Istanbul) Constantine the Great, closed the Baalbek temples.  At the end of the century, he tore down the altars of Great Court outside the Temple of Jupiter; later the stones and other pieces were used to construct a basilica.   In the 638 AD, the Muslim army occupied Baalbek, and used the ruins are a reinforced fortress.  Along the perimeter of the ruins, remain the walls and even a moat, created by the Muslim army.  Even the remains of a mosque can be seen.