It is an Egyptian Temple located in the government agora. It was dedicated to the Egypt Goddess Isis. Later in Roman time, it was dedicated to the Roman Emperor Augustus. This was the first temple dedicated to an Egyptian goddess.
There is another temple dedicated to an Egyptian goddess named Serapes Temple. There was always a good relationship between Ephesus and Egypt in the ancient times. There were some Egyptian businessmen living in Ephesus. That’s why Egyptian temple were built in Ephesus.