Great coins have been shown above of Elagabalus' mother and grandmother. The prelude to his brutal downfall in March AD 222, was probably the adoption of his cousin, 13 year old Alexander Severus, in June 221. With Alexander Severus in line of succession, the unpopular 18-year old Elagabalus was rapidly becoming expendable. Here is a recent Ebay pickup of mine. A coin of Alexander Severus as Caesar, when he was still named Marcus Aurelius Alexander. His early coins as Caesar are quite scarce. M AVR ALEXANDER CAES // PIETAS AVG
Here is the Sestertius version of the OP coin: And here are Sestertii of Elagabalus´ grandmother, mother, and (2nd/4th) wife: Julia Maesa Julia Soaemias Aquilia Severa