Chapter 8 is titled “Of the Beginning of Political Societies” and attempts to argue logically how at least some governments must have appeared due to people banding together voluntarily for their common defense.
Locke tries to explain how the leadership he often observed in his day and in history developed, and how older monarchies differed from ones around his time.
I won’t say that his arguments are airtight, but if we take care to understand how the scope of Locke’s “state of nature” differs from Hobbes’s, Locke does in fact make some good points.
Locke refers to a couple of historical sources that I managed to track down:
Jose de Acosta’s “Natural and Moral History of the Indies”
https://archive.org/details/naturalmoralhist00acos/page/n5/mode/2up
https://archive.org/details/naturalmoralhist01acos/page/n9/mode/2up
“Justin,” a.k.a. Marcus Junianius Justinus Frontinus’s
“Epitome of Pompeius Trogus’s ‘Philippic Histories'”
https://www.attalus.org/info/justinus.html