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, A in wreath below.
SNG ANS 616 ff.; Le Rider p. 31, 9 - 11, and pl. 45, 29 - 30.

Courtesy of Forum Ancient Coins online shop.