Complex sentence: However the earlier claim that the river's name literally means' carnage'persisted, with the alleged' goddess' even entered some encyclopaedias, and has since become casually conflated with the similarly named Welsh river Aeron.
Split into simpler sentences: However the earlier claim that the river's name literally means' carnage'persisted. The alleged' goddess'even entered some encyclopaedias, and the derivation to' carnage' has since become casually conflated with the similarly-named Welsh river Aeron.