Complex sentence: Founded in 1727, the academy is the oldest Catholic school in the United States, and was the oldest continuously operating school for women in the United States until damage from Hurricane Katrina closed it for remainder of the fall 2005 semester.
Split into simpler sentences: Founded in 1727, the academy is the oldest Catholic school in the United States, and is the oldest continuously operating school for women in the United States. However damage from Hurricane Katrina closed it for part of the fall 2005 semester.