The siege of Lisbon, from 1 July to 25 October 1147, was the military action against the Almoravid dynasty that brought the city of Lisbon under the definitive control of the new Christian power, the Kingdom of Portugal. The siege of Lisbon was one of the few Christian victories of the Second Crusade—it was "the only success of the universal operation undertaken by the pilgrim army", i.e., the Second Crusade, according to the near contemporary historian Helmold, although others have questioned whether it was really part of that crusade. It is seen as a pivotal battle of the wider Reconquista.