Watch List notes:

Attica, Athens AR Tetradrachm. Circa 454-404 BC. Head of Athena right, wearing crested Attic helmet ornamented with three olive leaves above visor and spiral palmette on bowl, round earring with central boss and pearl necklace / Owl standing to right with head facing, olive sprig and crescent behind, ΑΘΕ before, countermark: winged animal (Pegasos?) to right; all within incuse square. Kroll 8; Dewing 1591-8; SNG Copenhagen 31. 17.18g, 25mm, 8h.

Extremely Fine; extremely rare and unusual countermark.

From the inventory of a UK dealer.