LONDON — Politician John Hume, who won Nobel Peace Prize for work to end violence in his native Northern Ireland, has died, his family said. He was 83.

The former lawmaker had dementia and had suffered ill health for a number of years.

The Catholic leader of the moderate Social Democratic and Labour Party, Hume was seen as the principal architect behind the peace agreement. He shared the prize with the leader of the Protestant Ulster Unionist Party, David Trimble, for their efforts to end the sectarian violence that plagued the region for three decades.

A civil rights leader who joined the Northern Irish civil rights movement in the 1960s, Hume saw nationalism as a declining force. He sought the notion of extending self-government to Northern Ireland with power divided among the groups forming it.

“Ireland is not a romantic dream; it is not a flag; it is 4.5 million people divided into two powerful traditions,″ he said. “The solution will be found not on the basis of victory for either, but on the basis of agreement and a partnership between both. The real division of Ireland is not a line drawn on the map, but in the minds and hearts of its people.”

While both Hume and Trimble credited the people of Northern Ireland and the Irish Republic, it was Hume’s diplomacy that offered the impetus to the peace process.

Hume won a breakthrough in Belfast’s political landscape in 1993 by courting Gerry Adams, the head of Sinn Fein, the political wing of the Irish Republican Army, in hopes of securing an IRA cease-fire.

Hume had envisioned a broad agenda for the discussions, arguing they must be driven by close cooperation between the British and Irish governments. The process was overseen by neutral figures like U.S. mediator George Mitchell, with the decisions overwhelmingly ratified by public referendums in both parts of Ireland.

″Without John Hume there would not have been a peace process,″ Mitchell said at the time the prize was announced. ″Without David Trimble there would not have been a peace agreement.″