Complex sentence: From Safi and Azemmour, the Portuguese cultivated the alliance of local Arab and Berber client tribes, notably a certain powerful Yahya ibn Tafuft, and began sending armed columns inland, subjugating the region of Doukkala and soon encroaching on Marrakesh.
Split into simpler sentences: From Safi and Azemmour, the Portuguese cultivated the alliance of local Arab and Berber client tribes in the surrounding region, notably a certain powerful Yahya ibn Tafuft. The Portuguese and their allies dispatched armed columns inland, subjugating the region of Doukkala and soon encroaching on Marrakesh.