St. Josaphat of Polotsk
In 1054, a formal split called a schism took place between the Eastern Church centered in Constantinople and the Western Church centered in Rome. Trouble between the two had been brewing for centuries because of cultural, political, and theological differences. In 1054 Cardinal Humbert was sent to Constantinople to try and reconcile the latest flare up and wound up excommunicating the patriarch. The immediate problems included an insistence on the Byzantine rite, married clergy, and the disagreement on whether the Holy Spirit proceeded from the Father and the Son. The split only grew worse from there, centering mostly on whether to except the authority of the Pope and Rome.
More than five centuries later, in what is now known as Byelorussia and the Ukraine but what was then part of Poland-Lithuania, an Orthodox metropolitan of Kiev and five Orthodox bishops decided to commit the millions of Christians under their pastoral care to reunion with Rome. Josaphat Kunsevich who was born in 1580 or 1584 was still a young boy when the Synod of Brest Litovsk took place in 1595-96, but he was witnessto the results both positive and negative.
Many of the millions of Christians did not agree with the bishops decision to return to communion with the Catholic Church and both sides tried to resolve this disagreement unfortunately not only with words but with violence. Martyrs died on both sides.Josaphat was a voice of Christian peace in this dissent.