In ancient Egyptian history, the Old Kingdom is the period spanning c. 2700–2200 BC. It is also known as the "Age of the Pyramids" or the "Age of the Pyramid Builders", as it encompasses the reigns of the great pyramid-builders of the Fourth Dynasty, such as King Sneferu, under whom the art of pyramid-building was perfected, and the kings Khufu, Khafre and Menkaure, who commissioned the construction of the pyramids at Giza. Egypt attained its first sustained peak of civilization during the Old Kingdom, the first of three so-called "Kingdom" periods (followed by the Middle Kingdom and New Kingdom), which mark the high points of civilization in the lower Nile Valley.
The concept of an "Old Kingdom" as one of three "golden ages" was coined in 1845 by the German Egyptologist Baron von Bunsen, and its definition evolved significantly throughout the 19th and the 20th centuries. Not only was the last king of the Early Dynastic Period related to the first two kings of the Old Kingdom, but the "capital", the royal residence, remained at Ineb-Hedj, the Egyptian name for Memphis. The basic justification for separating the two periods is the revolutionary change in architecture accompanied by the effects on Egyptian society and the economy of large-scale building projects.