A church has stood on St. George Hill (, translit. "sviatoyurs'ka hora") since around 1280, dating back to a time when the area was still part of the Principality of Halych-Volhynia. After the original wooden church and the fortress it was situated in were destroyed by King Casimir III of Poland in 1340, a four-column Byzantine basilica was constructed for the local Eastern Orthodox Church. In July 1700, the Act of Unification of the Lviv archeparchy with the Holy See (the Bishop of Rome – the Pope) was proclaimed in this older version of St. George's when Bishop Joseph Shumlanskyi openly embraced the Union of Brest (1596).