Religion in Roman Egypt was complex. Since the Ptolemaic period (c.305 – 30 BCE), Greek gods had become more popular in Egypt, but Egyptian gods continued to be worshipped, especially Isis.
This period saw the expansion of the cult of Isis across the entire Roman Empire. Images of Isis nursing her son Horus remained popular throughout Egypt.
However, most Egyptian religion remained local to particular regions of Egypt. People in Egypt would continue to revere local gods. Animal god remained popular, such as Isis-Thermouthis. This could change by location. In the Fayum, the crocodiles were holy. At Oxyrhynchus, sharp nosed fish were defied.
People would attend processions and celebrate festival days. They might visit oracles or stay in healing centres (a Greek practice that become important in Egypt during this period). The normal people would practice a folk religion, much of which has disappeared from the historical and archaeological record.
Temples were supported by the Roman state, but in decreasing amounts. Roger Bagnall has estimated that but the third century most Egyptian temples were financially struggling. By the Fourth Century, Christianity spread in popularity. Many areas had numerous churches. Monasteries replaced temples in importance.