I recently received an uncleaned lot of coins, and these were my two favorite ones in it. The sestertius is a coin of Severus Alexander, the last emperor of the Severan dynasty. The other coin is a billion tetradrachm. However, I don't know who is on the coin. It doesn't look like Septimius Severus, or any other coins I have seen with bearded emperors. If you know, please tell me. Thanks a lot.