About a decade later, in violation of the Gulistan Treaty, the Russians invaded the Erivan Khanate. This sparked the final bout of hostilities between the two; the Russo-Persian War of 1826-1828. In the early stages of this war, the Iranians were successful in recovering many of the territories that were lost in 1813; however, the Russian offensive of 1827, in which the superior Russian artillery played a decisive role, resulted in the Iranians being defeated at Abbasabad, Sardarabad as well Erivan. Erivan was taken by the Russians on 2 October 1827. In February 1828, Iran was forced to sign the Treaty of Turkmenchay, which resulted in the cession of the khanate (as well as the other remaining territories to the north of the Aras River) to the Russians. After the fall of the Soviet Union, the Aras River became and remained the border between Iran and Armenia.