Complex sentence: The name Young Ireland was originally used in a disparaging way to describe the group of Repeal Association members associated with "The Nation" newspaper who were campaigning for the repeal of the Act of Union 1800 between the kingdoms of Great Britain and Ireland.
Split into simpler sentences: The name Young Ireland was originally used in a disparaging way to describe the group of Repeal Association members associated with "The Nation" newspaper. The Repeal Association was at the time, campaigning for the repeal of the Act of Union 1800 between the kingdoms of Great Britain and Ireland.