Two acts were passed in 1800 with the same long title, An Act for the Union of Great Britain and Ireland. The short title of the act of the British Parliament is Union with Ireland Act 1800, assigned by the Short Titles Act 1896. The short title of the act of the Irish Parliament is Act of Union  1800, assigned by a 1951 act of the Parliament of Northern Ireland, and hence not effective in the Republic of Ireland, where it was referred to by its long title when repealed in 1962.. How many years passed between the renaming of the Act of Union 1800 and its repeal?