More about him: https://uniasancta.wordpress.com/2019/07/03/prayer-to-st-josaphat-kuntsevych/

O Saint Josaphat, wonderful Saint and heroic martyr for the union of our Church with the Vicar of Christ, the Pope of Rome. Thou are glorious on account of thy zeal in the propagation of the true Catholic faith among our people. Thou art wonderful because of thy heroic martyrdom for the unity of faith of our people with the Holy See of Rome, the true center of orthodox Catholicism.

Thou art admirable on account of thy sublime virtues with which thou has adorned thy soul. We admire thy ardent love for Jesus and Mary and thy allegiance to the Vicar of Christ. Thou art a sublime example of all virtues for the people of whom thou wert born. Since thou art so powerful with God as thy miracles prove, I ask thee to obtain for me from Jesus and Mary a strong attachment to the Catholic faith and to Eastern Catholics faithfulness to their beautiful Eastern Rite, which we shall never betray nor abandon. Obtain also the grace of indefatigable zeal that I may labor for the reunion of my separated Eastern Brethren.

O glorious martyr of our Catholic Church, remember the nation of which thou wert a son, look at your people and pray to God for future reunion of all Eastern rite Christians under one fold and one shepherd. May the day come soon in which all thy Brethren will assemble before thy holy relics to give thanks to God for the union of all Christians with the Holy See. Amen.

Adapted from : https://uniasancta.wordpress.com/2019/07/03/prayer-to-st-josaphat-kuntsevych/