Meanwhile, the "Reconquista" continued in the north throughout the 12th century. As various Arab lands fell to the Christians, conditions for some Jews in the emerging Christian kingdoms became increasingly favorable. As had happened during the reconstruction of towns following the breakdown of authority under the Umayyads, the services of Jews were employed by the victorious Christian leaders. Sephardic knowledge of the language and culture of the enemy, their skills as diplomats and professionals, as well as their desire for relief from intolerable conditions — the very same reasons that they had proved useful to the Arabs in the early stages of the Muslim invasion — made their services very valuable.