He held this office until February 1812, when he retired, partly from dissatisfaction at the inadequate support given to Wellington by the ministry, but also because he had become convinced that the question of Catholic emancipation could no longer be kept in the background. From early life Wellesley had, like his brother Arthur, been an advocate of Catholic emancipation, and with the claim of the Irish Catholics to justice he henceforward identified himself. On Perceval's assassination he, along with Canning, refused to join Lord Liverpool's administration, and he remained out of office till 1821, criticising with severity the proceedings of the Congress of Vienna and the European settlement of 1814, which, while it reduced France to its ancient limits, left to the other great powers the territory that they had acquired by the Partitions of Poland and the destruction of the Republic of Venice. He was one of the peers who signed the protest against the enactment of the Corn Laws in 1815. His reputation never fully recovered from a fiasco in 1812 when he was expected to make a crucial speech denouncing the new Government, but suffered one of his notorious "black-outs" and sat motionless in his place.