A triumvirate is any group or set of which number?
Correct answer: 3

That Cøunt, Ray Bumpkin
Player #53553731, did you realise that all the answers are some form of three?

Tom
The description misses a major point.
Two powerful men would conflict with each other. A third was added to reduce this one-to-one conflict. Also, judges are often chosen in odd numbers, even numbers can tie.

Phantom.Mike
The Han Dynasty dates in the answer are broken.