Iry-Hor

Iry-Hor or Ro (as read by Petrie) was a Predynastic pharaoh of ancient Egypt, although some archaeologists are doubtful of his existence. He was most likely Ka's immediate predecessor. He ruled over Abydos and was buried in its local cemetery at Umm el-Qa'ab near Ka, Narmer and the First Dynasty kings.
If he existed, he would be the earliest documented person.