Answer:
William the Conqueror's 1066 invasion of England did indeed further the concept of law in ways still practiced today by introducing the Norman legal system to England[1][2][3]. This system was based on the idea of feudalism and was characterized by the king's ownership of all land and the granting of land to his vassals in exchange for their loyalty and military service. William's reach extended into the Church and the legal system, and he needed to ensure the direct loyalty of his feudal tenants. The 1086 Oath of Salisbury was a gathering of William's tenants-in-chief and other important landowners who took an oath of fealty to William[4].