After the defeat of Mark Antony and Cleopatra, Octivan later to be called Augustus Caesar made Egypt his personal property and instituted a unique coinage for that country. The coins show the head of the current emperor and a very large diversity of Roman, Greek and Egyptian themes on the reverse side of the coin. Nearly all of the coins show the Emperor's Alexandria reign year date. This allows us to date the coins to +/- one year.
The coin shown is a tetradrachm of Severus Alexander (reigned 222 to 235 CE) with the reverse Greek date IB representing the year 12. This corresponds to 232/233 CE.