Alan IV, Duke of Brittany of William the Bastard, Duke of Normandy (later to become known as William the Conqueror) support of rebels in Brittany against Alan's maternal uncle, Conan II. Conan II died in late 1066 during a campaign in Anjou, and was succeeded by Alan's parents, Conan's sister Hawise and her husband Hoel II. Hoel ruled as regent from Hawise's death in 1072 until Alan reached his majority in 1084. To prevent further hostilities during his invasion of England, William I married his daughter Constance to the new duke Alan in 1087. The marriage ceremonies may have taken place in Bayeux in Normandy.
William Augustus, Duke of Brunswick-Harburg France and England and then enrolled with his brothers at the University of Helmstedt. In 1594, he again went on a journey that took him through Germany, Poland, Switzerland, Italy, Holland, Denmark and Livonia. William Augustus kept a journal about his travels. After the death of his father, he took up the government of Harburg jointly with his brothers Christopher and Otto III. After they died, he ruled alone. In 1618, William Augustus began the construction of the palace at Moisburg. After the death of the Duke Frederick Ulrich of Brunswick-Wolfenbüttel, he received the County of Hoya from his inheritance.