After Alexander the Great's conquest of Persia in the 330s BC, Baalbek (under its Hellenic name Heliopolis) formed part of the Diadochi kingdoms of Egypt & Syria. It was annexed by the Romans during their eastern wars. The settlers of the Roman colony Colonia Julia Augusta Felix Heliopolitana may have arrived as early as the time of Caesar but were more probably the veterans of the 5th and 8th Legions under Augustus, during which time it hosted a Roman garrison. From 15 BC to AD 193, it formed part of the territory of Berytus. It is mentioned in Josephus, Pliny, Strabo, and Ptolemy and on coins of nearly every emperor from Nerva to Gallienus. The 1st-century Pliny did not number it among the Decapolis, the "Ten Cities" of Coelesyria, while the 2nd-century Ptolemy did. The population likely varied seasonally with market fairs and the schedules of the Indian monsoon and caravans to the coast and interior.