Historical non-fiction depicting smart, clever masterminds or fiction where clever person doesn’t feel like an omnipotent wizard?

Basically a smart person who is demonstrably smart by doing believable, clever research and decision making. Not looking for battle tactics. More like social maneuvering between powerful forces. Those forces can be important politicians, geopolitics, monarchies, spies I don't care.

Prefer non fiction history but will accept fiction if believable and clever.