The Thirteenth Dynasty of ancient Egypt (notated Dynasty XIII) is often combined with Dynasties XI, XII and XIV under the group title Middle Kingdom. Some writers separate it from these dynasties and join it to Dynasties XIV through XVII as part of the Second Intermediate Period. Dynasty XIII lasted from approximately 1803 BC until approximately 1649 BC, i.e. for 154 years. According to Kim S. B. Ryholt, the 13th Dynasty was a continuation through a female line of the preceding 12th Dynasty, with its first pharaoh, Sobekhotep I, a son of queen regnant Sobekneferu and her husband Amenemhat and not a son of Amenemhat IV, as often stated. Amenemhat IV in reality died childless. Kim Ryholt proposes that the demarcation between the two dynasties reflects the rise of the independent 14th Dynasty in the eastern Delta, an event which, he proposes, occurred during Sobekneferu's reign. As direct heirs to the kings of the 12th Dynasty, pharaohs of the 13th Dynasty reigned from Memphis over Middle and Upper Egypt, all the way to the second cataract to the south. The power of the 13th Dynasty waned progressively over its 150 years of existence and it finally came to an end with the conquest of Memphis by the Hyksos rulers of the 15th Dynasty, c. 1650 BC. Rulers In later texts, this dynasty is usually described as an era of chaos and disorder. However, the period may have been more peaceful than was once thought since the central government in Itj-tawy near the Faiyum was sustained during most of the dynasty and the country remained relatively stable. The period was undoubtedly characterized by decline, with a large number of kings with short reigns and only a few attestations. The true chronology of this dynasty is difficult to determine as there are few monuments dating from the period. Many of the kings' names are only known from odd fragmentary inscriptions or from scarabs. The names and order in the table are based on Dodson and Hilton and Ryholt. Following these kings, the remaining rulers of the 13th Dynasty are only attested by finds from Upper Egypt. This may indicate the abandonment of the old capital Itjtawy in favor of Thebes. Daphna Ben Tor believes that this event was triggered by the invasion of the eastern Delta and the Memphite region by Canaanite rulers. For some authors, this marks the end of the Middle