On the sudden decease of Alexander, the czar of all the Russias, amid the southern steppes, a revolution induced by the nobility broke out at Petersburg, but was suppressed by Alexander's brother and successor, the emperor Nicholas I. Nicholas had wedded Charlotte, the eldest daughter of the king of Prussia. This energetic sovereign instantly invaded Persia and rendered that country dependent upon his empire without any attempt being made by the Tory party in England and Austria to hinder the aggrandizement of Russia, every attack directed against her being regarded as an encouragement to liberalism. Russia consequently seized this opportunity to turn her arms against Turkey, and, in the ensuing year, a Russian force under Count Diebitsch, a Silesian, crossed the Balkan (Haemus) and penetrated as far as Adrianople; while another corps d'armée under Count Paskiewicz, advanced from the Caucasus into Asia Minor and took Erzerum. The fall of Constantinople seemed near at hand, when Austria and England for the first time intervened and declared that, notwithstanding their sympathy with the absolute principles on which Russia rested, they would not permit the seizure of Constantinople. France expressed her readiness to unite with Russia and to fall upon the Austrian rear in case troops were sent against the Russians.[2] Prussia, however, intervened, and General Muffling was dispatched to Adrianople, where, in 1829, a treaty was concluded, by which Russia, although for the time compelled to restore the booty already accumulated, gained several considerable advantages, being granted possession of the most important mountain strongholds and passes of Asia Minor, a right to occupy and fortify the mouths of the Danube so important to Austria, and to extend her aegis over Moldavia and Wallachia.
In the midst of this wretched period, which brought fame to Russia and deep dishonor upon Germany, there still gleamed one ray of hope; the Customs' Union was proposed by some of the German princes for the more intimate union of German interests.