Complex sentence: After recieving use of the Barracks via lease in 1907 the buildings were not occupied then in 1915 the St. Francis Barracks were gutted in a fire however the original coquina stone walls remained standing.
Split into simpler sentences: After recieving use of the Barracks via lease in 1907 the buildings were not occupied at that time. In 1915 the St. Francis Barracks were gutted in a fire however the original coquina stone walls remained standing.