I go with the books that taught me the most when I first started collecting seriously, ancient is is pre 1500 per Wayne Sayles series. The fall of Constantinople in 1453 was one of the factors that ignited the renaissance. I am jealous of your Constantine XI @Voulgaroktonou , to have a coin from the last Ruler of the Romans.At least that is what they called themselves and so did their enemies who surrounded them. In the West during the Holy Roman Empire they called them the Greeks. Here is my John VIII SBCV-2564 7.14gm 1425-1428 AD
I recently purchased this silver Hexagram of emperor Heraclius. This coin is currently my youngest ancient coin. The silver Hexagrams were minted when Byzantine Empire was experiencing successive invasions from the Persians, Avars, and Arabs. The economy was so depressed that Heraclius resorted to confiscating silver plates from churches to mint his Hexagrams. The silver Hexagram would pay the wages of Heraclius’s army as they campaigned to reconquer lost territory from the Persians. Heraclius & Heraclius Constantine AR21 Hexagram. Constantinople Obv: Heraclius and Heraclius Constantine seated facing on double throne, each holding globus cruciger. δδ NN ҺЄRACILЧS ЄT ҺЄRA CONST. Rev: Cross potent set upon globus set upon three steps; K to right. δЄЧS AδIЧTA ROMANIS. SB 798. 6.06 g. 610-641 AD.
It's hard to say when antiquity ends and when medieval times begin so I put in three contenders: 1. My youngest coin (ironically the very first ancient coin I bought) before the fall of the Western Empire in 476, which is often cited as the end of antiquity: Constans, 9 September 337 - 19 January 350 A.D. Bronze AE 3, RIC VIII Thessalonica 120, LRBC II 1642, SRCV 18732, Cohen VII 10, F, corrosion, encrustation, 2.493g, 18.6mm, 180o, Thessalonica (Salonika, Greece) mint, 348 - 350 A.D.; obverse D N CONSTA-NS P F AVG, pearl-diademed, draped, and cuirassed bust right; reverse FEL TEMP REPARATIO (happy times restored), Constans standing left on galley, holding labarum and Phoenix on globe, Victory seated in stern steering ship, TES[...] in exergue; 2. Youngest coin before the end of late antiquity, around the time when the Muslims arrive as a major player on the world stage and this emperor just so happens to be the ruler who witnessed it: Byzantine Empire, Heraclius & Heraclius Constantine, 23 January 613 - 11 January 641 A.D. Gold solidus, Wroth BMC 76; Tolstoi 410; DOC II-1 44f (no examples in the collection, refs Wroth); SBCV 770; Hahn MIB 53; Sommer 11.35; Morrisson BnF -, aEF, luster, tight flan, graffiti on obverse and reverse, 4.336g, 19.3mm, 180o, 8th officina, Constantinople (Istanbul, Turkey) mint, 639(?) - 641; obverse Heraclius in center taller with mustache, long beard; standing with Heraclius Constantine on right, Heraclonas on left, sons beardless and equal height, all wear crown, chlamys and tablion ornamented with pellets, and hold globus cruciger in right; reverse VICTORIA AVGu H (victory of the Emperor, 8th officina), cross potent on three steps, Heraclian monogram left, E right, CONOB in exergue; 3.Youngest coin from a civilization that lived through antiquity, so technically not even "ancient" anymore, it's pretty firmly medieval, but it's from the Eastern Roman/Byzantine Empire (I also just want an excuse to show it off since it's beautiful and I haven't shown it on this site yet): Byzantine Anonymous Follis of Christ, Class A3, Basil II & Constantine VIII, c. 1023 - 11 November 1028 A.D. Bronze anonymous follis, Anonymous follis of Christ, DOC III-2, class A3; SBCV 1818; Grierson-NumisWiki ornaments F1c, gVF, attractive bust of Christ, tight ragged flan, bumps and marks, edge chip, 8.514g, 27.9mm, 270o, Constantinople (Istanbul, Turkey) mint, c. 1023 - 11 Nov 1028 A.D.; obverse + EMMANOVHL (romanized Hebrew - God is with us), facing bust of Christ, wearing nimbus cruciger, pallium, and colobium, holding gospels with both hands, IC - XC (Greek abbreviation: Ihsoús Xristós - Jesus Christ) across field; reverse + IhSuS / XRISTuS / bASILEu / bASILE (Greek: Jesus Christ King of Kings), ornamentation above and below inscription; unpublished variety;
My favorite period is 1st Century BC - I tend to think of Ancient as anything from the beginning of time until the fall of Rome (5th Century AD), "Byzantine & Medieval" from the fall of Rome (5th Century AD) until the Italian Renaissance (14th century AD) and the rest Modern Arcadius is the last of the Roman emperors in my collection (so far) This coin, Anastasius Solidus, I catalog under "Byzantine & Medieval" more on this coin here: https://www.sullacoins.com/post/gold-rush
My collection stops at Honorius/Arcadius, so unless things change, I guess they'll always be the youngest in the collection. Here's my example for the moronic Arcadius, don't have his slightly less moronic brother yet Edit: Guess I shoulda added, (383-408)
Since I do a talk on Ancient History as Shown by Coins at a high school, it's almost a requirement for me to have the 1st and the last "Ancient" coins so as to delineate the period for the students. This being high school I go along with the teachers and class curricula who define the Ancient era as ending in 476 AD with the Fall of the Western Roman Empire. I won't display my first here but here is my latest Ancient Coin. Rome, Western-Imperial, Julius Nepos, 474-475, & 480 AD. Gold tremissis, 1st reign (474-475 AD) direct purchase from Ed Waddell (Ed's photo: I should retake in high res) Aside from wear, this piece has no flaws and is well-struck. I did recently (January 2019?) bid on the Heritage tremissis of Romulus Augustus (476 AD) which had SCRATCHES on both sides but that piece went for a huge sum. Romulus Augustus was not recognized by the East so Julius Nepos is the last legally recognized Western Roman Emperor. Given the high prices of Romulus, I will not make that a priority in Ancients buying as this Nepos is good enough.
My youngest ancient to date is this from 352-355 AD Constantius II AE reduced. Rome AD 352-355, under Constantivs II. OBV: DN CONSTAN – TIVS PF AVG Laurel and rosette-diademed, draped and cuirassed, right. B behind bust. REV: FEL TEMP RE – PARATIO Soldier, helmeted, draped and cuirassed advancing left and spearing fallen horseman with right hand and wearing shield on left arm. Shield on ground to right of horseman wearing pointed cap, falling forward clutching horse’s neck. Gamma in left field, R wreath Z in exergue. 22mm, 5.21g Ric VIII Rome 257. Purchased from Castellet Classical Numimatics