Complex sentence: Kel Ayr (also Kel Aïr) were a semi-nomadic Tuareg tribal confederation, which ruled an area centered on the Aïr Mountains (Aïr Massif) in what is today Niger.
Split into simpler sentences: Kel Ayr (also Kel Aïr) was a semi-nomadic Tuareg tribal confederation. It ruled an area centered on the Aïr Mountains (Aïr Massif) in what is today Niger.