You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
One example: Category: HOMOPHONIC PAIRS 
Clue: It's a notation on a percussion store to clash
Solution is here: cymbal symbol
Explanation: "Cymbal" and "symbol" both have the same pronunciations but different meanings, hence they are homophonic pairs. A symbol is the notation and a cymbal is a percussion instrument that clashes and rings.

Now, solve this: Category: HISTORIC ROYALTY 
Clue: These two men seen here, allies during World War I, were sometimes mistaken for each other
Solution:
czar nicholas ii & king george v