Complex sentence: When the British took over the territory the political authority of the Caliphate was abolished and put under the Northern Nigeria Protectorate; however, the title of Sultan was retained and remains an important religious position for Muslims in the region to the current day.
Split into simpler sentences: When the British took over the territory, they abolished the political authority of the Caliphate and put the area under the Northern Nigeria Protectorate; however, the title of Sultan was retained. It remains an important religious position for Muslims in the region to the current day.