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.

For thousands of years, Abydos has been the city of the dead. It’s one of Egypt’s most sacred and ancient burial sites, guarding the secrets of many kings and important people from Egyptian society. So it’s not exactly surprising that archaeologists in Abydos uncovered the tomb of a pharaoh.

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.