Web site: https://www.ancient-jewellery.com/
This is an ancient Roman gold Solidus of emperor Theodosius II, who reigned from 408 - 450 A.D.
D N THEODOSIVS P F AVG,
D[ominvs] N[oster] THEODOSIUS P[ivs] F[elix] AVG[vstvs] "Our Lord Theodosius, Dutiful and Wise Augustus" helmeted, cuirassed three-quarters-facing bust, spear over shoulder and shield decorated with horseman spearing enemy.
VOT XXX MVLT XXXX, Constantinopolis enthroned left, her left foot resting on a prow, holding a globus cruciger and a sceptre, a star on right.
This coin was struck at the Constantinople mint, between the years 430 - 440 A.D. It bears the Officina letter H(eta) on the end of the reverse legend after MVLT XXXX H, this indicates the coin to have been minted by the 8th Officina at the Constantinople mint. mintmark CONOB. This coin has seen plenty of circulation and likely formed part of the payment to Atilla the Hun of over 2100 Ilbs (in weight) of gold tribute per year (see Roman Gold and Hun Kings for further discussion)
DATE: 430 - 440 A.D.
MINTMARK: COMOB (Constantinople, Turkey)
SIZE: 21mm diameter
WEIGHT: 4.42 grams
ATTRIBUTION: (RIC 257; Hahn 25b).