Simplify the following text for a Grade 11 native English-speaking person.
Original: w : The Sanatorium of Bellevue ( 1857-1980 ) , which occupied part of the old monastery , played an important role in the history of Kreuzlingen .
Simplified: The Sanatorium of Bellevue ( 1857 â `` 1980 ) , which occupied part of the old monastery , played an important role in the history of Kreuzlingen .