It was founded in 724 AD by the itinerant bishop Pirmin. Built between the 9th and 11th centuries, the island's three Romanesque churches epitomise early medieval architecture.
At the time of the Carolingians and Ottonians they were regarded as the intellectual outposts of the western world. The church wall paintings illustrate the island's importance as a centre of European art in the 10th and 11th centuries.
Eminent scholars taught at the renowned abbey school, which produced outstanding theologians, politicians, scientists, poets and musicians.
Other famed establishments included the abbey library, Reichenau art school and the goldsmiths. It has been a UNESCO-World Heritage since 2000.