Philip II of Macedonia, 359-336 BC, AR fifth Tetradrachm or Tetrobol. 
14.5 mm, 2.524 gr. Amphipolis.

Diademed head of Apollo right.
FILIPPOY, Nude horseman cantering right, shield seen from the side below.
SNG ANS 733 (same reverse die); Le Rider p. 318, 18 - 19.

Courtesy of Forum Ancient Coins online shop.