SAN DIEGO — A palm-sized sandstone object found in 1991 at an Early Islamic trading outpost in what’s now southern Jordan appears to be the oldest known chess piece.

This roughly 1,300-year-old rectangular piece of rock with two hornlike projections on top resembles several rooks, also known as castles, that have been found at other Islamic sites in the region. But those other rooks date to a century or more later, John Oleson, an archaeologist at the University of Victoria in Canada, said. He presented his analysis of the carved rock on November 21 at the annual meeting of the American Schools of Oriental Research.

Simpler board games than chess go back roughly 4,000 years in Eurasia (SN: 11/16/18). Surviving written accounts indicate that chess originated in India at least 1,400 years ago, Oleson said. Merchants and diplomats probably carried the game westward. The suspected chess piece, excavated at Humayma, located on what was once a major trade route, dates to between 680 and 749, when an Islamic family owned and ran the site.

“Chess became very popular in the early Islamic world,” Oleson said. It also brought together people with diverse backgrounds. Islamic texts from that time portray chess matches between Muslims and Christians and between rich and poor players.

Rooks from southwestern Asia in the shape of two-horse chariots date to as early as the late 700s. The two-pronged shape of early Islamic rooks may have been meant to represent such chariots, Oleson said.

The possibly record-setting Humayma rook is now stored at the University of Victoria. At his home nearby, Oleson noted ruefully, his 10-year-old grandson regularly beats him at chess.