How did the worship of Isis and Serapis spread from Delos to Rome?

The worship of Isis and Serapis spread from Delos to Rome primarily through the expansion of Mediterranean trade networks.12

Initially, the cult of Serapis was established on Delos while the island served as a naval base for Greco-Egyptian kings. Even after Egyptian political influence on the island receded, the cult persisted and flourished. As the Romans subsequently utilized Delos as a free port for the eastern Mediterranean, the worship of these deities traveled along established trade routes to various harbors across the Greek world.12

From these maritime hubs, the cults reached cities in the Bay of Naples, where Italian merchants were instrumental in bringing the worship of Isis and Serapis to Rome. Once introduced to the capital, these religions gained popularity among diverse social groups, particularly in trading towns and seaports, eventually becoming widespread throughout Italy during the 1st and 2nd centuries CE.132