Review at BMCR of JHF Dijkstra, Philae and the End of Ancient Egyptian Religion: A Regional Study of Religious Transformation (298-642 CE) by Robert Gozzoli at the University of Siam. A rewrite of his PhD, Dijkstra asks what happened to the cults at Philae in the Late Antiquity? What was the role played by Christianity on the island? And was Philae exceptional?
The original PhD can be downloaded here, but note that it is a hefty pdf file.