When Mehemet Ali had announced his intention of shaking off his allegiance, Mahmud had seemed to defer to the pacific counsels of the Powers, and had refrained from ordering his troops in Asia Minor to invade Syria. But, before the spring of 1839, it was clear that he was resolved to appeal to arms, and that all the efforts of diplomacy to prevent a renewal of the conflict would be fruitless. It was not alone his bitter hatred of his rebellious vassal which prompted the Sultan to disregard the advice of the ambassadors at Constantinople. His sole claim to the Khalifate rested upon the protection of Mecca, and, inasmuch as Mehemet Ali was in possession of the Holy Cities, were he to declare himself independent, Mahmud must forfeit his right to command the temporal obedience of Mohammedans. Already Constantinople was seething with disaffection, and he is said to have been aware that a plot had been formed to depose him and to enthrone his son, under the guardianship of Mehemet Ali.[472] Mahmud was dying from a complication of disorders, but he gave his whole expiring strength to his military preparations. Men, horses and guns were hurried across the Bosphorus and forwarded to Hafiz Pasha in Asia Minor. Moltke with his plane-table was busily engaged in exploring the country up to Nezib, "a small town hidden among the olive trees close against the Syrian frontier."[473] At the news that the Porte was bent upon war, Mehemet Ali, curtailing his visit to Khartum, hastily returned to Cairo, whilst at Constantinople the ambassadors made a last endeavour to dissuade the Sultan from disturbing the peace.[474] But Mahmud was not to be diverted from his object, and in Paris, on May 23, 1839, it was known that Hafiz Pasha had crossed the Euphrates and that hostilities were about to begin.