Up until the Norman conquest of England, Wales had remained for the most part independent of the Anglo-Saxon kingdoms, although some Welsh kings did sometimes acknowledge the Bretwalda. Soon after the Norman conquest of England, however, some Norman lords began to attack Wales. They conquered and ruled parts of it, acknowledging the overlordship of the Norman kings of England but with considerable local independence. Over many years these "Marcher Lords" conquered more and more of Wales, against considerable resistance led by various Welsh princes, who also often acknowledged the overlordship of the Norman kings of England.