After World War I, Strumica and the surrounding area were broken away from the region and were ceded to Yugoslavia.[citation needed] It usually refers to the part of the region of Macedonia attributed to the Kingdom of Bulgaria by the Treaty of Bucharest (1913).Until World War I, the region included the areas of present-day Strumica and Novo Selo Municipality, today in North Macedonia.[citation needed] The main religion in the region of Pirin Macedonia is Christianity, with majority of population belonging to the Bulgarian Orthodox Church.During the early centuries of Christianity, this region belonged to the ancient Roman province of Macedonia, and later it was under the jurisdiction of the Archbishopric of Ohrid, up to the 1767.