The parish of St. Theodosius was organized in Cleveland in 1896 by Carpatho-Rusyn immigrants living in Tremont. The founders had emigrated from Carpathian Ruthenia in Austria-Hungary (now Zakarpattia Oblast in present-day Ukraine) when the tide of Eastern European immigration to the American urban centers of the Northeast and Midwest was at an all-time high. They were originally Ruthenian Greek Catholics (also known as Byzantine Catholics) who became dissatisfied by their affiliation with the Catholic Church and followed Carpatho-Rusyn church leader Alexis Toth into Russian Orthodoxy. This same situation played out in many Eastern Catholic parishes in the US, and the results formed the core group of the present Orthodox Church in America (OCA).