An important town by the 9th century , the city has had a diverse population which has at times included Muslims ( Shias and Sunnis ) , Christians ( Catholics , Protestants , Nestorians , and Orthodox ) , Jews , Bahá ' ís and Sufis . Around 1900 , Christians made up more than 40 % of the city 's population ; however , most of the Christians fled in 1918 as a result of the fighting of the so-called Persian Campaign between invading British , Ottoman , and Russian forces during World War I , which did not respect Iranian sovereignty or neutrality , and the Armenian and Assyrian Genocides by Ottoman Empire
Armenian
Armenian Genocide
Urmia