Ambrose Vretta was born in Macedonia in 1859. He attended the Imperial Medical College in Constantinople (now Istanbul), then toured Europe and studied in Rome. He returned for a time to his homeland, but soon left due to ill treatment by the Turkish government. He moved to Russia, where he became acquianted with the Metropolitan of St. Petersburg. It is possible that he was [[ordination|ordained]] a priest during his time in Russia.
In 1892, Fr. Vretta, by this time a priest, arrived in America with the newly-appointed Bishop [[Nicholas (Ziorov) of Warsaw|Nicholas (Ziorov)]]. On [[May 17]], 1892, he oversaw the founding of St. Nicholas Russian Orthodox Church in Chicago, becoming its first pastor. Shortly after this, he also assumed pastoral responsibility for a new [[parish]] in [[Church_of_the_Three_Hierarchs_(Streator,_Illinois)|Streator, Illinois]].
During his time in Chicago, Fr. Vretta had a friendly relationship with the local Greek priest, Fr. Panagiotis (Peter) Phiambolis, concelebrating with him on numerous occasions in both the Greek and Russian parishes.