It did not begin suddenly at the end of the Twelfth Dynasty, and it was simply a convenient label for a chronological gap, since only the dates of its beginning and end are definitely known: it began with the death of Queen Sobekneferu, and lasted until Ahmose rose to power. Between these two dates was a period that was so poorly documented: knowledge of this period hardly extended further than the names of rulers in the King-Lists. At first, only the Thirteenth Dynasty obsessed power in the land. But then it encountered opposition from the princes of Xois and Avaris in the Delta. The Fifteenth and Sixteenth Dynasties, running concurrently with the Seventeenth, were eventually expelled by Ahmose.