The Catholic Association was an Irish Roman Catholic political organisation set up by Daniel O'Connell in the early nineteenth century to campaign for Catholic emancipation within Great Britain. It was one of the first mass-membership political movements in Europe. It organized large-scale public protests in Ireland. British Home Secretary (later Prime Minister) Robert Peel was alarmed and warned an associate of his in 1824, "We cannot tamely sit by while the danger is hourly increasing, while a power co-ordinate with that of the Government is rising by its side, nay, daily counteracting its views." The Duke of Wellington, Britain's prime minister and its most famous war hero, told Peel, "If we cannot get rid of the Catholic Association, we must look to civil war in Ireland sooner or later