Complex sentence: The first fully documented incident occurred on March 21,1952, when a large group of male University of Michigan students raided a female dormitory; this led to a widespread increase of panty raids across the nation.
Split into simpler sentences: The first fully documented incident occurred on March 21,1952, when a large group of male University of Michigan students raided a female dormitory. This led to a widespread increase of panty raids across the nation.