The 40th anniversary of a civil rights demonstration that changed the course of Irish history is being remembered at a conference in the Northern Irish city of Londonderry on Saturday, attended by Irish President Mary McAleese and Nobel Peace Laureate John Hume. 

The demonstration, since referred to as the Duke Street March, took place in the city (known to Irish Catholic Nationalists as Derry) on October 4, 1968, and marked the beginning of a civil rights movement aimed at ending discrimination against Northern Ireland's Roman Catholic population by the majority Protestant government. 

The march was violently broken up by police forces overwhelmingly composed of Protestants loyal to the British crown and inimical to Catholic civil rights. The violence marked the beginning of 30 years of sectarian violence known as the Northern Ireland Troubles. 

McAleese in her keynote address drew parallels between the then emerging Northern Ireland civil rights movement and similar youth movements that swept across the world in 1968, from Paris to Washington and South Africa. 

McAleese evoked the memory of "all those ... who set out 40 years ago ... to create a Northern Ireland where every man, woman and child, Protestant and Catholic, Unionist and Nationalist ... would share full equality of citizenship." 

A peace agreement was signed in Belfast in 1998 which ended the Troubles, and eventually led to a power-sharing government between pro-British and pro-Irish parties. 

"When we consider the extent of change already achieved, of sacrifices and compromises made on all sides, we take courage and hope. We look back, but there is no turning back," McAleese added. 

McAleese is the first president of the Republic of Ireland to have been born within Northern Ireland, a territory of 1.7 million people which is part of the United Kingdom. 

The power-sharing arrangement is not currently proceeding smoothly, however, with the two main parties of the Democratic Unionists and Sinn Fein deadlocked over political appointments. 

Hume, a nationalist leader who was awarded the Nobel Peace Prize jointly with Unionist leader David Trimble, in 1998 for their efforts in ending the violence, also addressed the conference. 

The Troubles claimed over 3,000 lives and stemmed from centuries of sectarian division and political strife between the native Irish Catholic population and Protestant settlers loyal to Britain.