Key People and Parties.

General Terms

The Troubles: Name given to the period of armed conflict in Northern Ireland, from the late 1960s and usually taken to have ended with the Good Friday Agreement in 1998.
Loyalist/Unionist: Supporters of the continuing status of Northern Ireland within the United Kingdom. Generally, though not exclusively, an ideology held by Protestants within Northern Ireland. The term loyalist is usually applied for more hard-line proponents of this position, or sometimes more specifically those who support the use of violence.
Republican/Nationalist: Supporters of Northern Ireland joining the Republic of Ireland to form a united Ireland. Generally, though not exclusively, an ideology held by Catholics within Northern Ireland. As with loyalist/unionist, the choice of the term ‘Republican’ or ‘Nationalist’ is usually made to distinguish between more hard-line (or paramilitary) proponents of this position, and more moderate groups or individuals.
Northern Ireland Assembly: The devolved government of Northern Ireland, seated in Stormont, Belfast. Elected members are known as Members of the Legislative Assembly (MLAs).
Good Friday Agreement: The political agreement, signed in April 1998, that established the basis for devolution of government for Northern Ireland and the principle that all parties should be committed to exclusively peaceful politics. Agreed between leading nationalist and unionist parties and the British and Irish governments, then subsequently supported by 71% of the population of Northern Ireland on a referendum. The DUP was the only leading party to oppose the Good Friday Agreement, though they now have agreed to share power with Republican politicians, and the First Minister of the devolved Assembly is from the DUP.

Political Parties

Alliance Party: Largest cross community party and usually associated with moderate unionism, the Alliance Party is long-established though has struggled to break the political dominance of the leading unionist and nationalist parties.
Democratic Unionist Party (DUP): Largest unionist political party, founded by Ian Paisley and now led by Peter Robinson. Traditionally, the more ‘hard-line’ of the two major unionist parties, the DUP is now however sharing devolved government with Sinn Fein.
Social Democratic and Labour Party: Previously the largest nationalist party, they consistently opposed the use of violence and were key to the Good Friday Agreement. Since then, they have been overtaken in the polls by Sinn Fein.
Sinn Fein: Largest Republican political party and closely aligned with the IRA.
Ulster Unionist Party (UUP): Currently the second largest unionist party, they were the largest party at the time of the Good Friday Agreement.
Progressive Unionist Party (PUP): Smaller loyalist party, representing a more left-wing and urban constituency.
Women’s Coalition: Cross-community political party formed to promote inclusion of women within the peace process. Contributed to the negotiation of the Good Friday Agreement; now dissolved.

Paramilitary Organisations

All of these groups are considered illegal/terrorist organisations in both the United Kingdom and the Republic of Ireland.
Provisional Irish Republican Army (PIRA or IRA): Main Republican paramilitary organisation. Declared a ceasefire in 1994, and re-declared in 1997 in the build-up to the Good Friday Agreement. Decommissioned their weapons in 2005. When people say the ‘IRA’ they are almost always referring to the Provisional IRA, though there are small dissident organisations that also claim the name, such as the Official IRA and the Real IRA. These groups reject the Good Friday Agreement and continue to use violence to try and achieve their goal of a united Ireland.
Ulster Defence Association (UDA): Loyalist paramilitary organisation. Declared a ceasefire in 1994 and completed decommissioning their weapons in January 2010.
Ulster Volunteer Force (UVF): Loyalist paramilitary organisation that called a ceasefire in 1994 and completed decommissioning their weapons in 2009.

Politicians

Gerry Adams: President of Sinn Fein and leader throughout the Peace Process. Often alleged that he is/was a member of the IRA, a claim that Adams has always denied.
Tony Blair: British Prime Minister 1997-2007 who helped negotiate the talks that led to the Good Friday Agreement of 1998 -arguably one of his most notable achievements.
John Hume: Founding member of the SDLP and key architect of the Good Friday Agreement. Received the Nobel Peace Prize in 1998, jointly with David Trimble; retired from politics in 2004.
George Mitchell: Former US Democrat Senator who was Bill Clinton’s Special Envoy for Northern Ireland and who was credited with playing a key role in bringing about the Good Friday Agreement. Currently special envoy to the Middle East for the Obama administration.
Martin Maguinness: Deputy First Minister of the Northern Ireland Assembly and MP and MLA (Mid-Ulster) for Sinn Fein. A member of the IRA during the Troubles (he claims to no longer be a member), he was a leading negotiator for the Good Friday Agreement. A sign of the remarkable transformation of his public perception is that he was recently voted the most respected politician in Northern Ireland.
Ian Paisley: Co-founder of the DUP, its leader and dominant figure until his resignation as leader in 2008. Paisley is also a Protestant Minister and co-founder of the Free Presbyterian Church.
Ian Paisley Jr: Son of Ian Paisley and a leading figure of the DUP.
Iris Robinson: Wife of Peter Robinson and also MP and MLA for the DUP, she resigned from the NI Assembly and UK parliament after a damaging scandal in January 2010.
Peter Robinson: Long-term Deputy to Ian Paisley within the DUP who is now the First Minister of the Northern Ireland Assembly and MP and MLA for the DUP.
David Trimble: Ulster Unionist Party leader during the negotiation of the Good Friday Agreement, he was key to securing the support of his party and the wider unionist community for the Agreement. Received the Nobel Peace Prize in 1998, jointly with John Hume. Now a peer in the British House of Lords for the Conservative Party.