In 1826 the Duke of Wellington, the commander of the allied forces against Napoleon, who was now a senior statesman in the British government, travelled to St Petersburg to negotiate an Anglo-Russian accord (later joined by France in the Treaty of London in 1827) that would mediate between the Greeks and Turks. Britain, Russia and France agreed to call for the establishment of an autonomous Greek province under Ottoman sovereignty. When the Sultan rejected their proposals, the three powers sent a combined naval force under the command of the fiery British philhellene Admiral Edward Codrington, with instructions to impose a resolution by peaceful means if possible, and ‘by cannon’ as a last resort. Codrington was not known for diplomacy, and in October 1827 he destroyed the entire Turkish and Egyptian fleets in the battle of Navarino. Enraged by this action, the Sultan refused any further mediation, declared a jihad, and rejected the Russian ultimatum to withdraw his troops from the Danubian principalities. His defiance played into Russia’s hands.
Nicholas had long suspected that the British were unwilling to go to war for the Greek cause. He had been considering an occupation of the principalities to force the Turks into submission, but feared that would encourage the British to renounce the Treaty of London. Now the Sultan’s rejection of his ultimatum had given him a legitimate excuse to declare war against Turkey without the British or the French. Russia would fight on its own to secure a ‘national government in Greece’, Nesselrode wrote to Kapodistrias in January 1828. The Tsar sent money and weapons to Kapodistrias’s revolutionary government, and received from him an assurance that Russia would enjoy an ‘exclusive influence’ in Greece.18
In April 1828 a Russian attack-force of 65,000 fighting men and Cossacks crossed the Danube and struck in three directions, against Vidin, Silistria and Varna, on the road to Constantinople. Nicholas insisted on joining the campaign: it was his first experience of war. The Russians advanced quickly (the land was full of forage for their horses) but then got bogged down in fighting around Varna, where they succumbed to the pestilent conditions of the Danube delta and suffered severe losses. Half the Russian soldiers died from illness and diseases during 1828–9. Reinforcements soon got sick as well. Between May 1828 and February 1829 a staggering 210,000 soldiers received treatment in military hospitals – twice the troop strength of the whole campaign.19 Such huge losses were not unusual in the tsarist army, where there was little care for the welfare of the serf soldiers.
Renewing the offensive in the spring of 1829, the Russians captured the Turkish fortress of Silistria, followed by the city of Edirne (Adrianople), a short march from Constantinople, where the cannons of the nearby Russian fleet could be heard. At this point the Russians could easily have seized the Turkish capital and overthrown the Sultan. Their fleet controlled the Black Sea and the Aegean, they had reinforcements on which they could draw from Greek or Bulgarian volunteers, and the Turkish forces were in complete disarray. In the Caucasus, where the Russians had advanced simultaneously, they had captured the Turkish fortresses of Kars and Erzurum, opening the way for an attack on Turkish territories in Anatolia. The collapse of the Ottoman Empire appeared so imminent that the French King Charles X proposed partitioning its territories between the great powers.20