As a means of recording the passage of time, the 11th century was that century which lasted from 1001 to 1100. In the history of European culture, this period is considered part of the High Middle Ages.
1054, the Great Schism, in which the Western (Roman Catholic) and Eastern Orthodox churches separated from each other. Similar schisms in the past had been later repaired, but this one continues after nearly 1000 years.