In 1826, the Duke having been appointed ambassador to St. Petersburgh, on the anniversary of the entrance of the allied army into Paris under his command, the Emperor Nicholas addressed a letter to him, in which he told him that in order to testify to him his particular esteem for his great qualities and for the distinguished services he had rendered to the whole of Europe, he had given orders that the Smolensko regiment of infantry, formed by Peter the Great, and one of the most distinguished of his army, which was formerly under the Duke's command in France, should thenceforward be called the Duke of Wellington's regiment. In 1827, on the death of the Duke of York, the public mind pointed to the Duke of Wellington as the fit successor of his royal highness in the important post of Commander-in-Chief, and he was immediately appointed. The Duke held this office until the appointment of Mr. Canning to be Prime Minister, when he resigned it, and also the Master-Generalship of the Ordnance. The circumstances attending this resignation must of course hold a prominent place in any memoir of the Duke. But there were personal matters mixed up in the affair, which make it necessary to enter into it at some length, for the better understanding of his Grace's character. On the death of the Earl of Liverpool, in the beginning of the year 1827, the king called on Mr. Canning to form an administration. As Mr. Canning had all along advocated Roman Catholic Emancipation, and as the cabinet of Lord Liverpool had firmly opposed that measure, it became a question how far the premiership of Mr. Canning would compromise the position of those who had hitherto acted with him in the cabinet of Lord Liverpool. The question very soon received a practical solution, by the simultaneous (though not concerted) resignation of six of the most influential members of the government, including the Duke of Wellington. The political friends of Mr. Canning, and those of his opponents with whom he was agreed on the Roman Catholic question, concurred in representing this act of the seceding ministers as a cabal against Mr. Canning; and the Duke of Wellington, more especially, was made the subject of most unsparing abuse. The ground of this was that he had not contented himself with resigning the office he held directly under the government, but had also resigned the command of the army, an office unconnected with politics. This was supposed to indicate some special determination to crush Mr. Canning.