context: Under the Capetian dynasty the French monarchy slowly began to expand its authority over the nobility, growing out of the Île-de-France to exert control over more of the country in the 11th and 12th centuries. They faced a powerful rival in the Duke of Normandy, who in 1066 under William the Conqueror (duke 1035–1087), conquered England (r. 1066–87) and created a cross-channel empire that lasted, in various forms, throughout the rest of the Middle Ages. Normans also settled in Sicily and southern Italy, when Robert Guiscard (d. 1085) landed there in 1059 and established a duchy that later became the Kingdom of Sicily. Under the Angevin kings of England of  (r. 1154–89) and his son Richard I of England (r. 1189–99), the kings of England ruled over England and large areas of France, brought to the family by Henry IIs marriage to Eleanor of Aquitaine (d. 1204), heiress to much of southern France. Richards younger brother John, King of England (r. 1199–1216) lost Normandy and the rest of the northern French possessions in 1204 to the French King Philip II of France (r. 1180–1223). This led to dissension among the English nobility, while Johns financial exactions to pay for his unsuccessful attempts to regain Normandy led in 1215 to Magna Carta, a charter that confirmed the rights and privileges of free men in England. Under  (r. 1216–72), Johns son, further concessions were made to the nobility, and royal power was diminished. The French monarchy continued to make gains against the nobility during the late 12th and 13th centuries, bringing more territories within the kingdom under the kings personal rule and centralising the royal administration. Under Louis IX of France (r. 1226–70), royal prestige rose to new heights as Louis served as a mediator for most of Europe.
question: How many years later did the Duke of Normandy conquer England after Robert Guiscard landed in Sicily?
answer: 7