The Church of the Apostles in the Castle District on the southern skirt of Kars Castle is one of the Armenian churches in the city and was built by King Abbas between 932-937 AD during the reign of Bagratli Kingdom.

The church has a central plan and a rectangular space that resembles four clover leaves and enlarges with four niches. Later, in 1064, this church was converted to a mosque in the region under the Muslim sovereignty and was named Kümbet Mosque. When the region came under Russian domination, the mosque was turned into the Russian Orthodox Church. In 1964, it was turned into a museum and the historical artifacts obtained from the excavations in Kars began to be exhibited here. This old place of worship, also known as the Kars Museum, continued this function until 1981. Since 1993 it is still used as a mosque.