For the first three centuries AD the Roman Emperors ruled Egypt as a kind of personal estate and governed it quite differently to the rest of their empire. For instance it had its own coinage, which blended Greek and Egyptian features. On the reverse of this coin is the god Zeus Ammon. Beside him are L, a symbol meaning 'year', and IH, Greek numerals representing '18'. This shows that the coin was minted in the 18th year of Antoninus Pius's reign (AD 154-155).