The burial chamber of a little known pharaoh called Senebkay, who reigned over 3,600 years ago, has been found 300 miles south of Cairo.
The skeleton of Senebkay was uncovered by a University of Pennsylvania expedition working with the Egyptian government, according to a report by the antiquities ministry.
The pharaoh has never featured in ancient Egyptian history books, but Senebkay's name was found inscribed in hieroglyphics written inside a royal cartouche, the Egyptian ministry said in a statement.
Photographs show a pharaoh's skeleton stretched out on a white sheet. "He was originally mummified but his body was pulled apart by ancient tomb robbers," said a ministry statement.
The mummy was found in a badly damaged wooden sarcophagus in a burial chamber, which has painted images on the walls.
According to the Luxor Times, the pharaoh would have been around 6ft tall.
Canopic jars, used to store internal organs such as the liver, stomach and intestines, were found in the tomb but no funerary furniture, which may have been stolen by ancient tomb robbers.
"No funerary furniture was found in the tomb, confirming it had been robbed in the ancient pharaonic ages," said Ali al-Asfar, an antiquities ministry official.
Joseph Wegner, head of the Pennsylvania expedition added: "The modesty of the size of the tomb points to the decline of economic conditions in this period".
Senebkay's reign was around 1650 BC, a time known as the second intermediate period, when central authority collapsed. Small kingdoms then sprang up between the end of the Middle Kingdom and the start of the New Kingdom.
The oldest known picture of a pharaoh was found carved on rocks at a desert site in southern Egypt, according to new research into long forgotten engravings.
Dating back more than 5,000 years, the images depict a pharaoh riding boats with attendant prisoners and animals on what is thought to be a tax-collecting tour.