Original: Old Kingdom is the name commonly given to the period in the 3rd millennium B.C.E. when Egypt attained its first continuous peak of civilization in complexity and achievement -- the first of three so-called '' Kingdom '' periods , which mark the high points of civilization in the lower Nile Valley ( the others being Middle Kingdom and the New Kingdom ) .
Simplified: It was the first of three so-called '' Kingdom '' periods , which mark the high points of civilization in the lower Nile Valley ( the others being Middle Kingdom and the New Kingdom ) .