P. M. Holt's The Sudan of the Three Niles is an annotated translation of the Funj Chronicle, a history of the Funj sultanate (1504–1821) based at Sennar, along the Blue Nile, and of the Turco-Egyptian regime that succeeded it at Khartoum. Along with the Tabaqat of Wad Dayf Allah (a biographical dictionary of Sudanese Muslim holy men compiled in the late 18th century), the Funj Chronicle is the most important Arabic source on the northern riverain Sudan in the Funj era, a period in which Islam was spreading widely and the region was developing its pronounced Arab–Islamic identity.