Archaeologists have discovered the large limestone burial chamber of an unidentified ancient Egyptian pharaoh near the city of Abydos dating to about 3,600 years ago during a chaotic period in Egypt's history.

The burial chamber most likely belonged to a ruler in a line of kings once lost to history, researchers said. “It’s a new chapter in investigating this dynasty,” one noted.

The burial chamber for the unnamed ruler was found in January in a sacred city where little is known about its ancient royalty.