Archaeologists refer to the second period of stability and prosperity in Ancient Egypt as the Middle Kingdom (2055–1650 BC). After the decline of the Old Kingdom around 2180 BC, Egypt entered a period of weak pharaonic power and decentralized rule known at the First Intermediate Period. Different regional powers competed against one another for influence and power until approximately 2055 BC when Mentuhotep II was able to conquer his rivals in both Upper and Lower Egypt and established the 11th dynasty with a capital at Thebes (modern Luxor). Uniting all of Egypt under a single government again, he established the Middle Kingdom.
Although united again, Egypt did not achieve the heights of power that produced the great pyramids of the Old Kingdom. The Middle Kingdom only lasted from the 11th dynasty through the 13th dynasty and the building that took place was on a much more modest scale suggesting that the kingdom and its economy were not as strong as during the Old Kingdom period. Between the 11th and 12th dynasties the center of power shifted from Thebes in the south to Lisht near the oasis of Fayoum. At Lisht the Middle Kingdom pharaohs built several pyramids of much more modest size than those that have made the Old Kingdom famous, but most of these are now ruined due to their inferior construction. After approximately 400 years and 3 dynasties, the 13th dynasty’s hold over Egypt deteriorated and the Nile Valley descended into a second period of disarray known as the Second Intermediate Period (1650-1550 BC).