Halfway through Edward Gibbon's Decline and Fall of the Roman Empire. Also reading Theodor Mommsen's history of Rome.
I've been desultorily reading through the Philokalia, which presents an eerily similar vision of meditation and spiritual progression as that of the Thai Wilderness tradition.
Makes me think of this sutta about the unvarying nature of spiritual purification:
https://www.dhammatalks.org/suttas/AN/AN10_95.html