Seleukos I - Basileus of Basileía tōn Seleukidōn from 305 BC to 281 BC
Seleukos I was one of the Diadochi - 'successors' to Alexander III 'the Great'.

Having previously served as an infantry general under Alexander the Great, he eventually assumed the title of basileus and established the Seleucid Empire over much of the territory in the Near East which Alexander had conquered.

Seleucus founded a number of new cities during his reign, including Antioch (300 BC) and in particular Seleucia on the Tigris (ca. 305 BC), the new capital of the Seleucid Empire, a foundation that eventually depopulated Babylon.
Seleukos I
King Seleukos I "the Victor" of the Seleucid Empire

Epithet: Nikator ("the Victor")

(1) Seleukos I 290-281 BC
AE unit Syria
Obverse: Winged head of Medusa right, locks of snake-hair protruding from forehead
Reverse: BASILEWS / SELEYKOY, bull butting right, uncertain control monogram between hind legs
Ref: None provided
(2) Seleukos I 296-280 BC
Obverse: Horned and bridled head of horse right
Reverse: Anchor, BAΣIΛEΩΣ // ΣEΛEYKOY, monogram
Ref: SC 146; ESM 46; SNG Spaer 135.
(3) Seleukos I 311-300 BC
Obverse: Head of Herakles right, wearing lion's skin
Reverse: BAΣIΛEΩΣ ΑΛΕΞΑΝΔΡΟΥ, Zeus Aëtophoros seated left; monogram in wreath in left field, HP monogram below throne.
Ref: SC 82.5a; Price 3746.
(4) Seleukos I 312-281 BC
Obverse: Head of Herakles right, wearing lion skin.
Reverse: Nike advancing right; A to right.
Ref: SC Ad76; HGC 9.57.