The city has been home to various ethnic groups during its history. The population of Urmia in the early Islamic period was Christian. At the beginning of the 20thcentury, the city had a significant Christian minority (Assyrians and Armenians). According to Macuch, and Ishaya, the city was the spiritual capital of the Assyrians, who were influenced by four Christian missions that had been established in the city in the period from 1830 to the end of World War I. A large number of the Assyrians and Armenians were killed in 1914 during the Armenian and Assyrian genocides, which resulted in a change in the city's demographics. During the era of Reza Shah Pahlavi, Iranian Assyrians were invited to return to the region, and several thousand did return. There are around 5,000 Assyrians remaining in the city.