Monarchy of the United Kingdom which resulted in a Danish monarchy for one generation. The conquest of England in 1066 by William, Duke of Normandy, was crucial in terms of both political and social change. The new monarch continued the centralisation of power begun in the Anglo-Saxon period, while the Feudal System continued to develop. William was succeeded by two of his sons: William II, then Henry I. Henry made a controversial decision to name his daughter Matilda (his only surviving child) as his heir. Following Henry's death in 1135, one of William I's grandsons, Stephen, laid claim to the throne and took power with
Henry I of France William until the former's death in 1060. In 1051, William married Matilda, the daughter of the count of Flanders, which Henry saw as a threat to his throne. In 1054, and again in 1057, Henry invaded Normandy, but on both occasions he was defeated. Henry had three meetings with Henry III, Holy Roman Emperor—all at Ivois. In early 1043, he met him to discuss the marriage of the emperor with Agnes of Poitou, the daughter of Henry's vassal. In October 1048, the two Henries met again and signed a treaty of friendship. The final meeting took place in May 1056