The cult of Isis at Philae goes back at least to the 7th century BC, but the earliest surviving remains date from the reign of the last native king of Egypt, Nectanebo I (380–362 BC). The most important ruins were begun by Ptolemy II Philadelphus (285–246 BC) and added to for the next 500 years until the reign of Diocletian (AD 284–305). By Roman times Isis had become the most popular of all the Egyptian gods, worshipped across the Roman Empire even as far as Britain. Indeed, as late as AD 550, well after Rome and its empire embraced Christianity, Isis was still being worshipped at Philae. Early Christians eventually transformed the main temple’s hypostyle hall into a chapel and defaced the pagan reliefs, their inscriptions later vandalised by early Muslims.