Welcome to Steemit! Thanks for your comments on my Contact posts. Up-voted and followed, though I'll be avoiding the Black Mirror posts until I get caught up.
Some friends of mine wrote a CoC sourcebook for 1st century Rome.
https://www.chaosium.com/invictus/
Cool. I never got to play CoC but always wanted to. Antiquity should go along very nicely with it. I think Lovecrafts' creatures were inspired at least partially by monsters like Scylla, Charybdis, Leviathan and the hydra.
It's a very popular game at conventions, should you find yourself at one.