The Good Friday Agreement of 1998 formalized power-sharing arrangements between unionists and nationalists. It's not always been a smooth process politically, with the two sides often unable to reach agreement on how to govern, and there's been sporadic outbreaks of violence.
“This anniversary reminds us of our complex history, and provides an opportunity to reflect on our togetherness and our diversity,” the queen said in a statement.
“It is clear that reconciliation, equality and mutual understanding cannot be taken for granted, and will require sustained fortitude and commitment," she added.
The queen also referred to “treasured” memories she shared in Northern Ireland with her late husband, Prince Philip, who died last month at 99.
British Prime Minister Boris Johnson also marked the date, describing it as a “very significant" anniversary and stressed the importance of reflecting on the “complex history” of the past 100 years.
"People from all parts of Northern Ireland, the Republic of Ireland, the United Kingdom and across the globe, will approach this anniversary in different ways, with differing perspectives,” he said.
In recent weeks, there have been outbreaks of violence across Northern Ireland, with the unionist community particularly aghast at post-Brexit trade rules that took effect this year. These imposed customs checks on some goods moving between Northern Ireland and the rest of the U.K., which did not exist when the U.K. was part of the EU.
Blinken urged all politicians and parties to prioritize peace and stability.
“The United States remains a steadfast supporter of a secure and prosperous Northern Ireland, in which all communities have a voice and can enjoy the gains of the hard-won peace," he told reporters on Monday.
Although no major celebrations were held, plans to mark the centenary this year included tree-planting projects. Every school was given a native tree to plant in their grounds and many will explore what the future will look like in the next 100 years.
“Across generations, the people of Northern Ireland are choosing to build an inclusive, prosperous, and hopeful society, strengthened by the gains of the peace process,” the queen said. “May this be our guiding thread in the coming years.”