A rare gold coin bearing the portrait of Egyptian Queen Berenice II, dating back approximately 2,200 years, has been discovered in an archaeological excavation at the City of David in Jerusalem, the Israel Antiquities Authority announced on Wednesday.

The coin, made of nearly pure gold, is believed to have been part of a special series, possibly intended to pay stipends to soldiers during the Ptolemaic period.

Experts say this is the first coin of its kind ever recovered in an organized excavation, and only about 20 similar coins are known worldwide.