A serious weakness amongst the Muslim conquerors was the ethnic tension between Berbers and Arabs. The Berbers were indigenous inhabitants of North Africa who had only recently converted to Islam; they provided most of the soldiery of the invading Islamic armies but sensed Arab discrimination against them. This latent internal conflict jeopardized Umayyad unity. The Ummayyad forces arrived and crossed the Pyrenees by 719. The last Visigothic king Ardo resisted them in Septimania, where he fended off the Berber-Arab armies until 720.