Seleukos I Nikator, Seleukid Kingdom. AR drachm, 293-280 BC. 4.26 g. Ekbatana mint. 

Head of Herakles right, wearing lionskin headdress.
BASILEWS SELEYKOY, Alexander III, wearing horned helmet and fluttering 
chlamys, riding on the horned Bucephalos galloping right, 
holding couched spear. The horse is also horned and has a 
panther skin for a saddle.
SW in lower left field, WP and WK monograms beneath the horse.

ESM 481; SC 209; Imhoof 13 in NZ 27; Moerkholm 142; Hoover HGC 38.

With permission of numislanz.de, Auktion 102, lot 289