That's a rareish quarter siliqua from Sirmium. Could be worth $300 or more. Here is a common type I sold for $80. Theodoric/Uncertain King in the name of Anastasius Mint: Sirmium 454 to 552 AD AR Quarter Siliqua Obvs: D N ΛNΛSTΛSIVS P P ΛVC, pearl-diademed, draped, and cuirassed bust right. Revs: star M INVIΛ A ROMA D, Theoderic monogram; cross above. 13x14mm, 0.64g Cf. Stefan 1-3