Robert I, duke of Normandy (died 1035)

1000 (M) was a leap year starting on Monday of the Julian calendar, the 1000th year of the Common Era (CE) and Anno Domini (AD) designations, the 1000th and last year of the 1st millennium, the 100th and last year of the 10th century, and the 1st year of the 1000s decade. As of the start of 1000, the Gregorian calendar was 5 days ahead of the Julian calendar, which was the dominant calendar of the time.

Robert I of Normandy, also known as Robert the Magnificent and by other names, was a Norman noble of the House of Normandy who ruled as duke of Normandy from 1027 until his death in 1035. He was the son of Duke Richard II; the brother of Duke Richard III, against whom he unsuccessfully revolted; and the father of Duke William who became the first Norman king of England after winning the Battle of Hastings in 1066. During his reign, Robert quarrelled with the church—including his uncle Robert, archbishop of Rouen—and meddled in the disorder in Flanders. He was finally reconciled with his uncle and the church, restoring some property and undertaking a pilgrimage to Jerusalem, during which he died.