Delos, Cyclades Islands. AR didrachm or stater. 7.60g. Before 470 BC. 

Lyre with seven strings.
Lyre with four strings within incuse square. 

Apparently unique and unrecorded. NAC 59, 601.

With permission of Numismatica Ars Classica, Auction 59, lot 601, April 2011.
Estimate: 4500 CHF.