Complex sentence: After 1763 this part of Louisiana was claimed by Great Britain as part of its West Florida colony; however, Spain gained control of it in about 1780--during the American Revolutionary War--and maintained its authority in the area for three decades.
Split into simpler sentences: After 1763 this part of Louisiana was claimed by Great Britain as part of its West Florida colony. However, Spain gained control of it in about 1780--during the American Revolutionary War--and maintained its authority in the area for three decades.