So, how about St. Josaphat?  The Saint of the Day for Nov. 12?  St. Josaphat was a monk and a priest in what is now Russia and preached union with Rome.  He managed to convince his most Orthodox diocese of unity.  However, he made enemies of both hard-core Russian Orthodox people and hard-core Latinizers.  He was accused of being too Catholic to some Russian Orthodox people, and too distrustful and too Orthodox by the Catholic bishops.  So he was killed by a mob action.  

he is the first Eastern Orthodox saint to also be canonized by Rome.

St. Josaphat was someone who preached against the split between Orthodox and Catholic Christianity.  

Oh, and the Josaphat/Jehoshaphat in scripture, was, it seems to me, someone who pursued alliance and religious reform.  So even if the point was not a specific religious one, cuz duh, Josaphat is not just a Christian character, religious study can serve as a powerful tool for bringing home a point about an issue that doesn't have a religious monopoly, but is centered in justice.  But someone who knows more about this feel free to chime in, as it's 2AM.