[Sidenote: Russian intervention] A quarrel with the Pasha of Acre, Abdallah, gave Mehemet Ali a chance for Egyptian aggrandizement in that direction. Egyptian forces under the command of Mehemet Ali's adopted son Ibrahim marched into Palestine and laid siege to Acre. That stronghold resisted with the same stubbornness that Bonaparte had encountered years before. The protracted struggle there gave the Sultan time to prepare an expedition wherewith to intervene between his warring vassals. He took the part of the Pasha of Acre. A proclamation was issued declaring Mehemet Ali and his son rebels. A Turkish army under Hussain Pasha entered Syria. The fall of Acre, while the relieving army was still near Antioch, enabled Ibrahim to throw his full force against the Turks. In the valley of the Orontes the two forces met. The Turkish vanguard was routed and the Turkish main column fell back on Aleppo, leaving Antioch and all the surrounding country to the Egyptians. The Pasha of Aleppo, won over by Mehemet Ali, closed the gates of his city against Hussain's disordered forces. The Turks retreated into the mountains between Syria and Cilicia. The Egyptians pursued. At the pass of Beilan a stand was made by Hussain. The fierce mountain tribes turned against him, and with their help Ibrahim won a signal victory over the Turks, on July 29. The retreat continued through Cilicia far into Asia Minor. After several months a new Turkish army under Reshid Pasha, Ibrahim's colleague in the siege of Missolonghi, advanced from the north. A pitched battle was fought at Konieh on the 21st of December. The Turks were utterly routed. The army was dispersed and Reshid himself was made a prisoner. The road to Constantinople now lay open to Mehemet Ali. Sultan Mahmoud was so alarmed that he turned to his old adversary, Russia, for help. General Muravieff was summoned to Constantinople and was empowered to make terms for Turkey with Mehemet Ali. [Sidenote: Affair of Quallah Buteau]