Watch List notes:

The Roman Empire

Severus Alexander, 222 – 235. Sestertius 222-231, Æ 23.64 g. Laureate bust r., with drapery on l. shoulder. Rev. The Emperor seated l. on platform; behind, officer and soldier and in front, Liberalitas with abacus standing l. Below, a citizen mounting steps. C 139. RIC 578.
Very rare. Brown tone and good very fine
Ex Numismatica Wien sale 4, 1974, 507.