Complex sentence: Founded in 1988 in Rennes through the influence of different specialists in Arthurian legend, local elected officials, artists and writers, since 1990 its headquarters has been in Château de Comper in Paimpont forest.
Split into simpler sentences: Founded in 1988 in Rennes through the influence of different specialists in Arthurian legend, local elected officials, artists and writers. Since 1990 its headquarters has been at the Château de Comper in Paimpont forest.