Complex sentence: The town's official history contains two "creation myths" that are untrue: one is that the Hathaways' given names (and hence the true source of the town's name) originally came from an erstwhile governor of Ohio, Joseph Medary.
Split into simpler sentences: The town's official history contains two "creation myths" that are untrue. One is that the Hathaways' given names (and hence the true source of the town's name) originally came from an erstwhile governor of Ohio, Joseph Medary.