In the lateral nave of the former post-Jesuit church, and now the Collegiate Church of Corpus, there is the Chapel of St Teresa, in which faithful of the Greek Catholic church gathered for services. After 1945, almost all Greek Catholics were deported to the Soviet Union, bishops of the Ukrainian Greek Catholic Church arrested and sentenced to long imprisonment, and the Greek Catholic Church delegalised in all communist countries. Many Greek Catholics converted to Roman Catholicism to avoid forced resettlement. Only one retired priest - Stanisław Fedorowicz remained in Jarosław due to old age. He was entrusted with the care of a few faithful. At the beginning services were held in the apartment of the priest at św. Ducha Street. At the end of 1945, the Greek Catholic parish church was acquired by the Jarosław parish church. Fr. Dean Władysław Opaliński agreed to celebrate services to the Greek Catholic faithful in the lateral chapel of the parish church, in the Chapel of St Teresa. For years it was the only place north of Przemyśl which was holding such devotions. Father Fedorowicz died in 1965. Since then, the ministry was held by priests from Przemyśl. Church services were attended by the faithful who returned to Jarosław after 1956, as well as the faithful from the surrounding area (e.g. from Sieniawa or Lubaczów). This state of affairs occurred until 1987, when thanks to the efforts of father Bronislaw Fila from the Parish of Corpus Christi, Greek Catholics retrieved the church of Transfiguration of Our Lord.