Troezen, Argolis, AR Tritartemorion, ca 450-425 BC, 10 mm,  0.52 g. 

Archaic head of Athena facing. 
TRO, upright trident within incuse square. 

Traité II-3, 692; BMC 1; Imhoof MG 133; Hoover HGC 794.
Very rare.

With permission of Roma Numismatics E-Sale 8, Lot 128, May 2014.