Duke of Normandy as the reign of William II (1035–87), the ruler of Normandy could style himself "prince and duke, count of Normandy" as if unsure what his title should be. The literal Latin equivalent of "Duke of Normandy", "dux Normanniae", was in use by 1066, but it did not supplant "dux Normannorum" until the Angevin period (1144–1204), at a time when Norman identity was fading. Richard I experimented with the title "marquis" ("marchio") as early as 966, when it was also used in a diploma of King Lothair. Richard II occasionally used it, but he seems to have preferred the title duke.
Frederick William, Duke of Courland Frederick William, Duke of Courland Frederick William (; 19 July 1692 – 21 January 1711) was Duke of Courland and Semigallia from 1698 to 1711. Frederick Wilhelm was the son of Frederick Casimir Kettler and Elisabeth Sophie of Brandenburg. During his reign the duchy was occupied by Swedish and later by Russian troops. Friedrich Wilhelm Kettler was born in 1692 in Jelgava in the family of Friedrich Casimir and his second wife Elizabeth Sophia. At the age of seven, after his father's death, in the 22 January 1698 he was appointed as the Duke of Courland and Semigallia, however, until