Short answers, pulled from the story.
The Old Kingdom of Egypt was a period of ancient Egyptian history spanning roughly 2686 to 2181 BC, most commonly covering the Third Dynasty through the Sixth Dynasty. It was Egypt's first sustained peak of civilization, the first of three "Kingdom" periods, and is also known as the "Age of the Pyramids."
The Old Kingdom is called the "Age of the Pyramids" because it encompasses the reigns of the great pyramid-builders of the Fourth Dynasty. King Sneferu perfected the art of pyramid-building, and the kings Khufu, Khafre, and Menkaure commissioned the pyramids at Giza.
Djoser, the first king of the Third Dynasty, was the first king of the Old Kingdom. He ordered the construction of the Step Pyramid at Saqqara, the necropolis of Memphis, with the help of his vizier Imhotep, who is credited with developing building in stone and conceiving the step pyramid form.
The German Egyptologist Baron von Bunsen coined the concept of an "Old Kingdom" as one of three golden ages in 1845. The definition evolved significantly throughout the 19th and 20th centuries.
Power gradually shifted from the pharaoh to hereditary regional governors called nomarchs during the Sixth Dynasty, and succession struggles likely followed the long reign of Pepi II, who ruled from 2278 to 2214 BC. A 22nd-century BC drought then prevented normal Nile flooding for some years between 2200 and 2150 BC, and the collapse was followed by decades of famine and strife.
A 2025 study in the journal Nature sequenced the whole genome of a high-status Old Kingdom man excavated at Nuwayrat, radiocarbon-dated to 2855 to 2570 BC. Most of his genome was associated with North African Neolithic ancestry, while about 20% could be sourced to the eastern Fertile Crescent, including Mesopotamia.