The Buried Pyramid is an unfinished step pyramid constructed c. 2645 BC for Sekhemkhet. He was the second king of the Third Dynasty of Ancient Egypt, which reigned over Egypt c. 2686–2613 BC and is usually placed at the beginning of the Old Kingdom of Egypt. Many historians believe that the third dynasty played an important role in the transition from Early Dynastic Period of Egypt to the Age of the Pyramids.