Ancient Byzantine Empire: gold tremissis of Justinian I, ca. 527-565 AD
Obverse: D N IVSTINIANVS P P AVI, pearl diademed, draped, cuirassed bust right. Reverse: VICTORIA AVGVSTORVM, Victory standing right, head left, holding wreath and cross on globe, star to right, mintmark CONOB.
NGC Mint State (Strike 5/5, Surface 4/5, "wrinkled"), cert #4170211-001. Ex-Classical Numismatic Group eAuction 294, Lot 820, 1/16/2013. Purchased raw.
Quoting the original CNG auction description: "Justinian I. 527-565. AV Tremissis (15mm, 1.50 g, 7h). Constantinople mint. Pearl-diademed, draped, and cuirassed bust right / Victory advancing right, head left, holding wreath and globus cruciger; star to right; CONOB. DOC 19; MIBE 19; SB 145. Good VF, slightly wavy flan, small edge split."
This one had a pleasant plastic outcome, garnering a "Mint State" grade at NGC, much to my amazement and delight. That's quite a boost from CNG's "Good VF" grade. The "slightly wavy flan" CNG mentioned came out as "wrinkled" on the NGC label, which is rather strange nomenclature, if basically accurate. In hand, the flan doesn't look terribly wavy. This is a smaller coin, so it would likely be more noticeable on a bigger piece.
Justinian the First, otherwise known as "Justinian the Great", was known for his legal reforms, which became the foundation upon which much modern civil law in the West rests to this day.