Watch List notes:

KINGS OF MACEDON. Antigonos II Gonatas, 277/6-239 BC. Hemiobol (Bronze, 22 mm, 5.67 g, 9 h), contemporary imitation, uncertain mint. Helmeted head of Athena to right. Rev. B A Pan right, erecting trophy to right; below legs Antigonos monogram. HGC 3.1, 1049. SNG Copenhagen -. Unusual style; possibly an early Celtic imitation. With an attractive, brownish-gold toning. Good very fine.
Ironically in case that this coin is indeed an early Celtic imitation, this type was struck to commemorate the victory of the united Greeks against the great Celtic invasion of 279 BC!.