The Old Kingdom was a dynamic period in Egyptian history, extending from the Third through the Sixth Dynasties (ca. 2649–2130 BCE). The first ruler of the Third Dynasty was Djoser, who ordered the construction of the Step Pyramid and funerary complex at Saqqara, the necropolis of Memphis. These were the earliest stone structures in Egypt. Djoser’s architect, Imhotep, is credited with the development of building with stone. High officials in the Third Dynasty built rectangular mudbrick structures, known today as mastabas, above their tombs in Saqqara. The Fourth Dynasty encompassed the reigns of the great pyramid-builders: first Sneferu, under whom the art of pyramid-building was perfected, and later Khufu, Khafre and Menkaure, who commissioned the Great Pyramids at Giza. The collapse of the Old Kingdom came after the reign of Pepy II, the fourth king of the Sixth Dynasty, when repeated failures of the annual Nile flood led to catastrophic famine. Web resources here and here.

Seated Scribe from the Tomb of Kai, Saqqara, Egypt. Painted limestone with rock crystal and magnesite eyes. Fifth Dynasty. Ca. 2450–2325 BCE. Musée du Louvre. Photo: Shonagon.