Historically and down to the present, the region has been home to many ethnic groups and languages, some going back before 1800, others having migrated there since then. Dar Fertit has never been a united polity. Until the 1840s it, along with the rest of modern-day South Sudan, was unclaimed by any state, in particular the Muslim sultanates with slave-based economies that filled modern day southern Chad and the northern Central African Republic (among them Dar Fur, Dar Runga, Waddai, Dar al-Kuti, etc.).[clarification needed] After that time, Egypt, then a domain of the Ottoman Empire, steadily expanded up the White Nile and then westwards, eventually annexing the region in 1873.