An example of one of the most famous of ancient coin types, the Athenian silver decadrachm, highlights the Oct. 2 auction in London by Roma Numismatics Ltd.

The Athenian decadrachm features a classic design from ancient Greece and is one of about 40 known real examples of the rarity.

The obverse of the decadrachm features a head of Athena wearing an earring, a necklace and a crested Attic helmet decorated with three olive leaves and a spiral palmette. On the reverse is Athena’s owl, facing front with its wings spread, along with an olive sprig in the corner and the abbreviated legend translating to “[coin] of the Athenians.”

Weighing in at a massive 43 grams, the decadrachm was the largest silver denomination ever issued by the city (worth 10 drachmas) and was apparently struck as a special issue.

Silver decadrachms are thought to have been issued to commemorate a battle victory or some other notable event, possibly the city-state’s victory over the Persians at the battle of Eurymedon in 467 B.C.

Once extremely rare, a hoard of Athens decadrachms totaling 13 examples was found in 1984, according to Wolfgang Fischer-Bossert’s 2008 The Athenian Decadrachm. Fischer-Bossert’s follow-up research terms the type of decadrachm offered here as the “avant-garde” style, suggesting that the engravers ignored instructions to design archaizing heads and instead produced this style, influenced by contemporaneous artwork.

In Extremely Fine condition, the example offered by Roma Numismatics has an estimate of £125,000 (about $193,344 in U.S. dollars).

All lots are subject to a 15 percent buyer’s fee.

The full catalog may be viewed online at www.sixbid.com, or through the firm’s website, www.romanumismatics.com.

For more information, write to the firm at 20 Hanover Sq., Mayfair, London, W1S 1JY, United Kingdom, telephone it at (011) 44 20 3178 2874 or email the business at info@romanumismatics.com.

Some additional highlights:

Greece, Sicily, Segesta, circa 400 B.C. silver tetradrachm, Lot 52, Extremely Fine.

Greece, Sicily, Akragas, circa 409 to 406 B.C. silver tetradrachm, Lot 64, “attractively toned,” EF.

Greece, Sicily, Syracuse, circa 490 to 485 B.C. silver tetradrachm, time of Gelon, attributed to the master of the large Arethusa heads, “apparently unique and unpublished reverse die,” reverse shows Arethusa wearing headband and choker, Lot 91, Good EF.

Greece, Sicily, Syracuse, circa 405 to 400 B.C. silver tetradrachm, time of Dionysios I, “the finest known example of this type,” Lot 116, Good EF.

Greece, Sicily, Syracuse, circa 404 to 400 B.C. silver tetradrachm, time of Dionysios I, “unsigned work by Kimon,” Lot 119, Good EF.

Greece, Thrace, Ainos, circa 410 B.C. silver tetradrachm, Lot 270, About EF.

Greece, Ionia, Miletos, circa 259 to 246 B.C. “Persic” silver stater, “only 14 surviving examples,” Lot 290, Good EF.

Greece, islands off Caria, Rhodos, circa 380 B.C. silver tetradrachm, Lot 308, “lightly toned,” Good EF.

Greece, Kyrenaica, Kyrene, late fifth century to fourth century B.C. silver tetradrachm, Lot 335, EF.

Greco-Baktrian Kingdom, circa 230 to 190 B.C. gold stater, Euthydemos I, “the third known example,” Lot 367, EF.

Greco-Baktrian Kingdom, circa 170 to 145 B.C. gold stater, Eukratides I, seventh known example, Lot 370, Mint State.

Roman Republic, circa 241 to 235 B.C. silver didrachm, anonymous issue, Rome, Lot 379, Good EF.

Roman Imperatorial, 40 B.C. silver denarius, Divius Julius Caesar, struck under the magistrate Q. Voconius Vitulus, “outstanding portrait of Caesar, engraved in fine style,” Lot 520, EF.

Roman Imperatorial, 43 to 42 B.C. silver denarius, Marcus Junius Brutus with P. Servilius Casca Longus, struck by military mint traveling with the army in western Asia Minor or northern Greece, “one of the finest known examples,” Lot 527, Fleur-de-Coin.

Roman Imperial, A.D. 36 to 37 gold aureus, Tiberius, Lugdunum, Lot 575, EF.

Roman Imperatorial, A.D. 80 to 81 bronze sestertius, Domitian as Caesar, unknown Balkan Imperial mint, Lot 631, Good EF.

Roman Imperatorial, A.D. 172 to 173 gold aureus, equestrian statue of Marcus Aurelius, Lot 680, Good EF.

Roman Imperatorial, A.D. 178 gold aureus, Commodus, Rome, Lot 689, EF.

Roman Imperatorial, circa A.D. 180 to 192 bronze medallion, Commodus, portrayed as a Roman Hercules, “unique,” provenance to 18th century Prince of Waldeck and Pyrmont Collection, Lot 690, Very Fine.

Roman Imperatorial, A.D. 200 to 201 gold aureus, Septimius Severus and Julia Domna, Rome, Lot 696, Fleur-de-Coin.

Roman Imperatorial, A.D. 294 gold aureus, Maximianus, Nicomedia, Lot 755, Good EF.

Roman Imperatorial, A.D. 321 to 322 gold aureus, Licinius II as Caesar, Nicomedia, perhaps 15 examples known, Lot 766, Fleur-de-Coin. ¦