When Pashkevich left Nakhichivan he entrusted the area to Prince Eristov, a Georgian, with Muravyov as his lieutenant. He gave them strict instructions to merely guard the province and make no aggressive move. Abbas Mirza did the obvious thing. Crossing the Aras unopposed he found himself facing Eristov with 4000 men and 26 guns, far more than he expected. Abbas withdrew, Eristov chased him for a while and returned to Nakhichivan. So far they were within their orders. When they heard that the Persian army was in a state of complete demoralization the temptation was too great. Setting off on 30 September they reached a place called Maraud, Abbas got behind them, but when news of the fall of Yerevan reached them the Persian army was seized with panic and dispersed. Muravyov now chose to be bold, or foolish. Concealing his plans from everyone including Eristov he left Marand on 11 October and headed south. By 13 October they were a few miles from Tabriz. The garrison fled, driven out, it is said, by the inhabitants. The gates were opened and the ancient and wealthy city of 60,000 inhabitants was occupied without opposition. Peace negotiations began immediately, but dragged on. Fighting resumed in January but the Persian army was too demoralized to fight. Urmia was occupied and Ardebil opened its gates. The Treaty of Turkmenchay was signed on 10 February 1828 giving the two Azerbaijani khanates of Yerevan and Nakhichevan to Russia. On 20 March 1828 Paskevich learned that Russia was now at war with Turkey.