Prior to the end of the Balkan Wars of 1912-1913 and during portions of World War I, the territory of Macedonia was served by the American Board of Commissioners for Foreign Missions (hereafter ABCFM) with headquarters in Boston, Massachusetts. The form of Protestantism promoted by ABCFM was Congregationalism but in the Balkans, they called their churches Evangelical, which is often used as a synonym for Protestants. After the end of World War I, the ABCFM was unable to continue to financially support and staff this mission field outside of Bulgaria as proper and turned their work in Macedonia (which had become part of the Kingdom of Serbs, Croats, and Slovenes, and later renamed Yugoslavia) to the Methodist Church, whose Board of Foreign Missions was located in New York, NY. The Congregationalists and Methodists have worked exceptionally harmoniously on the mission field in the Balkans, which was unusual among Protestants of that time.
"Congretional/Methodist Church in Macedonia,"
Occasional Papers on Religion in Eastern Europe: Vol. 38
, Article 5.
Available at: https://digitalcommons.georgefox.edu/ree/vol38/iss1/5