The earliest known electrum coins, Lydian and East Greek coins found under the Temple of Artemis at Ephesus, are currently dated to between 625 and 600 BC). These coins were issued either by the non-Greek Lydians for their own use or perhaps because Greek mercenaries wanted to be paid in precious metal at the conclusion of their time of service, and wanted to have their payments marked in a way that would authenticate them. These coins were made of electrum, an alloy of gold and silver that was highly prized and abundant in that area.