An Israeli lifeguard taking his regular morning swim off the Mediterranean coast in southern Israel discovered a 2,500-year-old marble talisman to ward off the evil eye, the Israel Antiquities Authority said Sunday.

The lifeguard turned over the ancient disc that once adorned the bow of an ancient warship or cargo ship to keep evil away, the Israeli archaeology body said.

Experts say the relic, discovered off the coast Palmahim beach where the ancient Yavne-Yam port city once stood, dates back to the 5th or 4th century B.C. The white disc, flat on one side and convex on the other, measures 8 inches in diameter. The center of the disc is perforated, and the remains of two circles are painted around the center of it to represent the pupil of an eye.