Complex sentence: Modern skepticism, however, has largely discredited this genealogy; and the real history of Toulouse recommences in 780 or 781, when Charlemagne appointed his son, Louis the Pious, King of Aquitaine, with Toulouse for his chief city.
Split into simpler sentences: Modern skepticism, however, has largely discredited this genealogy. The written record of Toulouse do not recommence until 780 or 781, when it was recorded that Charlemagne appointed his son, Louis the Pious, King of Aquitaine, who made Toulouse his chief city.