The Siglos denomination
The Siglos was a coin denomination in the Persian Achaemenid Empire, and was roughly equivalent to 7½ Attic obols. It was struck in silver.

In more understandable terms, it generally weighed 5.4 grammes, and was struck from circa 520 BC to 330 BC.
(1) Achaemenid Empire
An AR Siglos struck 455-420? BC in Sardis
Obverse: hero or king holding bow and dagger right

Reverse: incuse square; crescent countermark

Diameter: 15 mm
Die Orientation: -
Weight: 5.15 g
times of Artaxerxes I and Dareios II
Carradice type IV (early) A
(2) Achaemenid Empire
An AR Siglos struck 510/505-486 BC in Sardis
Obverse: Great King right bearded and crowned kneeling-running, drawing bow, quiver at shoulder

Reverse: incuse square

Diameter: 14.5 mm
Die Orientation: -
Weight: 5.3 g
No notes for this coin
Carradice type II: Carradice plate XI, 11 - 13; BMC Arabia p. 173, 185 ff.; SGCV II 3428; Klein 754; Noe Sigloi pl. XIII, 215 ff.; Carradice NC 1998 pl. 3, 58 ff; Asyut Hoard 714; Winzer 1.6; Sunrise 21. Common. 73935
An AR Half-Stater | Siglos struck 561-546 BC in Sardis
Obverse: Confronted foreparts of a lion and a bull

Reverse: Two incuse square punches

Diameter: 16 mm
Die Orientation: -
Weight: 5.41 g
No notes for this coin
SNG von Aulock 2877