The Emperor Worship Cult
The worship of rulers as gods originated from the east (eg. Asia Minor, Syria, Egypt). The Egyptians worshipped their Pharaohs as gods. This was adopted by the Ptolemies (successors of the Egyptian portion of the Greek Empire after the death of Alexander the Great). The Romans followed the practice after the death of Augustus Caesar (30B.C.- 14 A.D.) However some emperors (Caligula, Nero, Domitian) claimed deity for themselves while they are still alive. Domitian demanded public worship as "Lord and God." Aside from themselves, some emperors also made others god- for example Hadrian made his favourite slave boyfriend Antinous, who drowned, god (as we saw the fresco at the Delphi museum).
Pergamum became the Asian centre of emperor worship. By the second century, it already have three pagan temples, including one to Emperor Hadrian. Pergamum may be the place referred to "where Satan has his throne" (Rev.2:13). The book of Revelation may be written during Domitian's reign.
This veneration serves to establish political unity and affirm loyalty to Rome. It filled no religious needs. However it did present a problems to Christians who cannot affirm any man, god nor submit to any Lord except to Lord Jesus.
(statue of Emperor Hadrian from the Archaeological Museum of Olympia. May be a statue from the emperor worship cult temple)