Khakheperre Senusret II was the fourth pharaoh of the Twelfth Dynasty of Egypt. He ruled from 1897 BC to 1878 BC. His pyramid was constructed at El-Lahun. Senusret II took a great deal of interest in the Faiyum oasis region and began work on an extensive irrigation system from Bahr Yussef through to Lake Moeris through the construction of a dike at El-Lahun and the addition of a network of drainage canals. The purpose of his project was to increase the amount of cultivable land in that area. The importance of this project is emphasized by Senusret II's decision to move the royal necropolis from Dahshur to El-Lahun where he built his pyramid. This location would remain the political capital for the 12th and 13th Dynasties of Egypt. The king also established the first known workers' quarter in the nearby town of Senusrethotep (Kahun). Unlike his successor, Senusret II maintained good relations with the various nomarchs or provincial governors of Egypt who were almost as wealthy as the pharaoh. His Year 6 is attested in a wall painting from the tomb of a local nomarch named Khnumhotep II at Beni Hasan. Reign Co-regency Co-regencies are a major issue for Egyptologists' understanding of the history of the Middle Kingdom and the Twelfth Dynasty. The Egyptologist Claude Obsomer wholly rejects the possibility of co-regencies in the Twelfth Dynasty. The Eyptologist Karl Jansen-Winkeln having investigated Obsomer's work concluded in favour of co-regencies. Jansen-Winkeln cites a rock stele found at Konosso as irrefutable evidence in favour of a co-regency between Senusret II and Amenemhat II, and by extension proof of co-regencies in the Twelfth Dynasty. The Egyptologist William J. Murnane states that "the co-regencies of the period are all known ... from double-dated documents". The Egyptologist Thomas Schneider concludes that recently discovered documents and archaeological evidence are effectively proof of co-regencies in this period. Some sources ascribe a co-regency period to Senusret II's rule, with his father Amenemhat II as his co-regent. The Egyptologist Peter Clayton ascribes at least three years of co-regency to Senusret II's reign. The Egyptologist Nicolas Grimal assigns nearly five years of co-regency prior to sole accession to the throne. Length of reign The lengths of the reigns of Senusret II and Senusret III are one of the main considerations for discerning the chronology of the Twelfth Dynasty. The Turin Canon is believed to assign a reign of 19 years