An international team of archeologists have discovered a massive tomb that belonged to one of ancient Egypt ’s earliest pharaohs. However, the ruler’s identity remains a mystery—as do many details of his long-lost dynasty.

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 limestone burial chamber, about 23 feet underground, dates back around 3,600 years to a period of unrest known as the Second Intermediate Period. The tomb was found at the Anubis Mountain necropolis by experts from the University of Pennsylvania Museum and Egyptian archaeologists.