The Catholic Association was an Irish Roman Catholic political organization 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. 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."[1] 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."[2] To stop the momentum of the Catholic Association it was necessary to pass Catholic Emancipation, and so Wellington and Peel turned enough Tory votes to win. Passage demonstrated that the veto power long held by the Ultra-Tories faction of reactionary Tories no longer was operational, and significant reforms were now possible.[3]