The images of the carvings found on vertical rocks at Nag el-Hamdulab, four miles north of the Aswan Dam, depict a pharaoh riding boats with attendant prisoners and animals in what is thought to be a tax-collecting tour, the Discovery News reported.
"We don't know with certainty who the king represented at Hamdulab is. We can guess on paleographic and iconographic grounds," Maria Carmela Gatto, associate research scholar in Egyptology at Yale University and co-director of thee Aswan-Kom Ombo archaeological project in Egypt, said.
The carving style suggests that the images were made at a late Dynasty date, around 3200-3100 B.C. This would have been the reign of Narmer, the first king to unify northern and southern Egypt, thus regarded by many scholars as Egypt's founding pharaoh.
According to researchers, the rock drawings, dating back more than 5,000 years, appear to feature the earliest known depiction of a pharaoh.
"There are depictions of local rulers since the first half of the fourth millennium BC, but Hamdulab seems by date to be the earliest datable representation of a king wearing one of the recognisable crowns of the ruler of all Egypt, engaged in a labelled royal ritual," John Darnell, professor of Egyptology at Yale University, told Discovery News.
Earlier discovered in the 1890s by the archaeologist Archibald Sayce, the carvings remained unnoticed for over a century. In the 1960s, Egyptian archaeologist Labib Habachi photographed Sayce's drawings of the rock images, but never published them.
The researchers investigated a total of seven carvings, which feature scenes depicting hunting, warfare, and nautical festival events.
The most extensive rock art picture, nearly 10 feet wide, shows five boats, one of which carries an anonymous king holding a long sceptre and wearing the White Crown, a conical shaped headpiece that symbolised rulership of southern Egypt.
The king is followed by a fan-bearer and preceded by a dog and two standard-bearers. A falcon standard appears below the king, while three of the boats boast a standard with bull horns.
"The entire scene depicts the moment that the religious procession of pre-Dynastic Egypt became the triumphant tour of a tax-collecting monarch," the researchers said.
"The carvings may therefore be the earliest record of tax collection we have from Egypt, and the first expression of royal economic control over Egypt and most probably also Nubia," they concluded.