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.

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.

A 2014 excavation proved the Abydos Dynasty existed. Now, Archaeologists have found a second tomb, but the king's identity remains unknown.