Complex sentence: In the late 1700's and early 1800's, during the Napoleonic wars, the first designated patient-transport vehicles were developed and used-removable litters were a standard item on these vehicles.
Split into simpler sentences: In the late 1700's and early 1800's, during the Napoleonic wars, the first designated patient-transport vehicles were developed and used. Removable litters were a standard item on these vehicles.