Philip II of Macedonia, 359-336 BC, AR fifth Tetradrachm or Tetrobol. 
15.4 mm, 2.595 gr. Amphipolis.

Diademed head of Apollo right.
FILIPPOY, Nude horseman cantering right, L in a circle below.
SNG ANS 662; Le Rider pl 45, 17.

Courtesy of Forum Ancient Coins online shop.