Sneferu (snfr-wj "He has perfected me", from Ḥr-nb-mꜣꜥt-snfr-wj "Horus, Lord of Maat, has perfected me", also read Snefru or Snofru), well known under his Hellenized name Soris (Koinē Greek: Σῶρις by Manetho), was the founding pharaoh of the Fourth Dynasty of Egypt during the Old Kingdom. Estimates of his reign vary, with for instance The Oxford History of Ancient Egypt suggesting a reign from around 2613 to 2589 BC, a reign of 24 years, while Rolf Krauss suggests a 30-year reign, and Rainer Stadelmann a 48-year reign. He built at least three pyramids that survive to this day and introduced major innovations in the design and construction of pyramids.