Seleucid Kingdom
Antiochus I "Soter"
AR Tetradrachm (29mm, 15.82g)
Diademed head right
BASILEWS ANTIOXOU, Apollo sitting on Omphalos, resting hand on bow and testing arrow

Antiochus I was born in 324 or 323 BC, around the time of Alexander the Great's death. His father was Seleucus I, and his mother was the Sogdian princess Apama. He succeeded his father to the throne in 281 BC, and ruled for 20 years of continuous warfare, both against rival Greek states and marauding Celts. It was against those Celts that he earned his title Soter or "Savior" by crushing a Celtic war party with his war elephants (possibly a gift from the Mauryan king Ashoka). Antiochus was mortally wounded in battle in 261, and died a short time after.
I really like the Apollo sitting on the Omphalos imagery here, and on many other Seleucid coins. I am not entirely certain if there was a specific myth surrounding this image, but the Omphalos was traditionally held to be a sacred stone used to mark the "navel" or center of the world.