Scuba divers have discovered the largest trove of gold coins ever found off Israel’s Mediterranean coast – about 2,000 pieces dating back more than 1,000 years, the country’s antiquities authority said on Tuesday.

“The largest treasure of gold coins discovered in Israel was found in recent weeks on the seabed in the ancient harbour in Caesarea,” the authority said in a statement.

It was by pure chance that members of a diving club in the Roman-era port had come across the coins, which the authority said weighed nine kilograms (almost 20 pounds) but described as “priceless”.