Athens, Attica, AE21. Time of Hadrian and the Antonines.

Bust of Athena right, wearing crested Corinthian helmet and aegis.
AQHN vertically to left, Poseidon naked except for chlamys, 
standing right, striking with trident, and Athena, standing 
left, armed with shield and spear, standing to left and 
right of olive-tree, around which a serpent twines, and in 
the branches of which sits an owl.  

BMC Attica 706.

Ancient coin Art 2003. Found in an orphaned folder and
added June 2010.