15 This work of conciliation was consecrated not many years later by the blood of martyrdom. Josaphat Kuntzevitch, archbishop of Polotsk and Vitebsk, was famed for his holiness of life and apostolic zeal, and was an intrepid champion of Catholic unity. He was hunted down with bitter hatred and murderous intent by the schismatics and on 12th November 1623 he was inhumanly wounded and slain with a halberd. But the hallowed blood of this martyr too became in a manner the seed of the Church, for all the parricides save one, repenting of their deed, renounced schism and execrated their crime before they were put to death. It may also be attributed to the prayers of the holy martyr that Melety Smotritzky, who had been the bitter rival of Josaphat for possession of the see of Polotsk, returned to the Catholic faith in 1627 and, after a period of vacillation, for the rest of his life stoutly defended the return of the Ruthenians to the Catholic Church.
Source: Orientales Omnes Ecclesias (Vatican.va)