(CNN)Martin McGuinness, former IRA commander and Deputy First Minister of Northern Ireland, died Monday night after a short illness, according to a statement released by the Sinn Fein party. He was 66.
A controversial figure, McGuinness was a leader in the Irish Republican Army terrorist group before becoming Sinn Fein’s chief negotiator during the Northern Ireland peace process.
In a statement, Sinn Fein described him as a man of “great determination, dignity and humility.”
“He was a passionate republican who worked tirelessly for peace and reconciliation and for the re-unification of his country. But above all he loved his family and the people of Derry and he was immensely proud of both,” Sinn Fein President Gerry Adams said in a statement.
His death comes less than three months after he resigned as Deputy First Minister, sparking an election and threatening Northern Ireland’s fragile power-sharing arrangement.
He retired from politics on January 19, 2017, saying his health had been deteriorating.
Under their tribute, Sinn Fein wrote in Irish, “I measc laochra na nGael go raibh a anam dlis,” which translates as “May he rest in peace in the presence of Irish heroes.”
He is survived by his wife Bernie and four children.
‘I am an Irish Republican’
McGuinness grew up in Derry, the epicenter of “The Troubles,” Northern Ireland’s decades’ long sectarian conflict.
About 3,500 people were killed during the Troubles, a conflict between Catholic Irish nationalists, who wanted to join the Republic of Ireland, and Protestants who wished to remain part of the United Kingdom. It ran for three decades up until the Good Friday peace agreement in 1998.
Even McGuinness’s place of birth is a question of politics — the nationalists call it Derry while the unionists refer to it as Londonderry.
Despite working with the UK government for peace in Ireland, McGuinness remained opposed to British rule in Northern Ireland until the end of his life.
“I am an Irish republican,” he told CNN’s Nic Robertson. “An Irish republican is someone who believes that the British government should have no part to play in the life of this island. We believe this island should be free.”
McGuinness and Britain’s Queen Elizabeth II made history in 2012 when they shook hands during her visit to Northern Ireland, a symbol of repairing relations between the United Kingdom and its province.
British, Irish leaders react
Many high-profile politicians in the UK and Ireland were quick tooffer their condolences at the news of McGuinness’s death.
Irish President Michael Higgins said in a statement that McGuinness’s passing left a gap that would be “difficult to fill.”
“The world of politics and the people across this island will miss the leadership he gave, shown most clearly during the difficult times of the peace process, and his commitment to the values of genuine democracy that he demonstrated,” he said.
Former British Prime Minister Tony Blair, who was in Downing Street at the time of the Good Friday Agreement was signed in 1998, said peace in Northern Ireland would not have been possible without McGuinness.
“Once he became the peace maker, he became it wholeheartedly,” Blair said in a statement.
Blair added: “I will remember him therefore with immense gratitude for the part he played in the peace process and with genuine affection for the man I came to know and admire for his contribution to peace.”
British Prime Minister Theresa May said McGuinness made an “essential and historic contribution to the extraordinary journey of Northern Ireland from conflict to peace.”
Kyle Paisley, son of former Northern Ireland First Minister Ian Paisley, who McGuinness served alongside as Deputy First Minister, said on Twitter that McGuinness had shown care towards his father when he was suffering ill health.
“Look back with pleasure on the remarkable year he and my father spent in office together and the great good they did,” he wrote. “Will never forget his ongoing care for my father in his ill health.”
Brexit almost delivers for McGuinness
McGuinness may have passed away within striking distance of his most closely held wish — a unified Ireland.
In the recent UK referendum on Europe, a majority of Northern Ireland voters chose to remain within the European Union.
Among their concerns was the state of the border between the Republic of Ireland and Northern Ireland, currently governed by a common travel area which allows free travel between the two countries.
It was a key part of the Northern Ireland peace deal but under the UK government’s Brexit white paper, Downing Street only said it would “aim” to protect the open border.
McGuinness’ Sinn Fein party called for a referendum on Irish unity in the wake of Brexit, which would take Northern Ireland out of the United Kingdom.