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.

Category: CLASSICAL MUSIC 
Clue: Mendelssohn's "Songs without Words" were once the most popular pieces for this instrument
piano

Category: ANCIENT ROME 
Clue: This church faced periodic persecution for 300 years, until Constantine's conversion
christian church

Category: STORY SONGS 
Clue: A Johnny Cash song ends with a man deciding to name his son "Bill or George!  Anything but" this

sue