Complex sentence: Franklinton was founded in 1819, originally under the name of Franklin, but in 1826 the name was changed to Franklinton since there was already another town with the same name in St. Mary Parish.
Split into simpler sentences: Franklinton was founded in 1819, originally under the name of Franklin. In 1826 the town's name was changed to Franklinton, as there was already another town named Franklin in St. Mary Parish.