KARIN – Erzurum (old Armenian name Karin) is a city in the territory of Western Armenia located on a plateau at an altitude of 1,900 meters. Karin (Erzurum) is a capital of Western Armenia.

http://www.western-armenia.eu/stat.gov.wa/arm/2014/Nakhaqahagan_Hramanaqir_11_Garin-16.02.2014.pdf.pdf

Karin was founded in the 14th century BC by Karanni (1400 – 1375 BC), a ruler of the state of Hayasa. The city was called Karano by the Ancient Greeks and Kalikala by the Arabs. Byzantine Emperor Theodosius II (reigned 401 – 450 AD) reinforced the city and renamed it Theodosiopolis in 421 AD. In 502, the Persians temporarily seized control of the city, and did the same in the late 6th century when the majority of the city’s inhabitants were moved to Hamadan.
Since early Middle Ages, Karin has been a prominent center of Armenian carpet making. In 1048-49, the nearby ancient Armenian city of Artsn was plundered by the Persians, forcing its inhabitants to flee to Karin. The city was shortly renamed Artsn-Rum (meaning Arzan of the Rûm, i.e., Romans). With time, the city’s name transformed into Erzurum.
In 1071, Seljuk Turks took possession of the city and carried out severe massacres of its population. Greek chronicler John Skylitzes reported that during the seizure of Erzurum, the Seljuk Turks killed 140 thousand people. Although this number is most probably inflated, it reflects the heavy consequences of the Seljuk Turk siege on the local Armenian and Greek communities.
In 1201, the province of Erzurum along with the city was conquered by the Seljuks. In 1242, the city fell to the Mongol assault, which left the city completely looted.
In later years, a 15th-century Spanish historian described Erzurum as follows: “The city was located on a plateau, had a strong stone wall with towers, as well as a fortress. The city wasn’t very populated, and there was a beautiful church. Before, the city had belonged to Christian Armenians and had been mostly populated by them.”
In 1472, the region went under the Persian control. However, the Turks conquered Erzurum in 1522. In July 1829, Erzurum went under the brief control of Russia during the Russo-Turkish Was of 1828-29 but shortly returned to the Ottoman Empire in accordance with the September Treaty of Adrianople. Subsequently, the remains of Erzurum’s Armenian population would move to the Russian Empire.