When images of the Derry civil rights march of October 5, 1968, flashed across the world, Northern Ireland was suddenly destabilised.
The following year the sectarian dragon had been fully reawakened and the region was plunged into a near-revolutionary crisis, characterised by bitter intercommunal conflict and protracted violence and destruction on the streets.
Was there anything that could be done to assuage the hatreds, suspicions and fears long etched into folk memory? How could the task of attempting to close over the fissures running across Northern Ireland's society begin?
A few were coming to the conclusion that the education of children apart was approaching the root of the problem. These people were to be the founders of All Children Together.
In 1973, a letter from the Bishop of Down and Connor, Dr William Philbin, was read out at all Sunday Masses: the sacrament of confirmation would not be administered to Catholic children attending non-Catholic schools.
Bettie Benton, Cecilia Linehan (writer of the famous letter to the Belfast Telegraph) and other Catholic mothers with children in state schools were outraged. In 1972 they had set up special classes with trained catechists to prepare their children to make their confirmation.
They met to form ACT to campaign for integrated schools as a third choice for parents faced with a straight choice between Catholic and state (in effect, Protestant) schools. It was not long before they attracted the support of Protestant parents.
By December 31, 1973, the day when the new power-sharing Executive began work, 986 people had died violently in the Troubles convulsing Northern Ireland.
Basil McIvor, Unionist MP for Larkfield, was appointed the new Minister of Education. He had rapidly come to the conclusion that "the mixing of schoolchildren would contribute to the reduction of community tension in Northern Ireland".
The Executive approved and welcomed McIvor's shared school plan presented to the Assembly on April 30, 1974. But just a fortnight later Northern Ireland was plunged into chaos as the loyalist strike got under way. On May 27, the Executive fell and direct rule returned.
For the first time, however, integrated schools seemed an achievable objective and not a dreamer's fantasy. Would the direct rule ministers now grasp the shared schools nettle?
They soon found that they faced intense opposition, from the Catholic hierarchy in particular, to any attempt to experiment with integrated schools.
In the summer of 1976, the education minister, Roland Moyle, with senior civil servants, met Cardinal William Conway, Bishop Edward Daly and Bishop William Philbin in Armagh.
John Pitt-Brooke, in his confidential 'Note for the Record', reported that "Cardinal Conway's attitude was one of complete intransigence.''
He dismissed the idea as "trivial, irrelevant, and without popular support". The clergy would "wage a campaign to fight a proposal to set up an unwanted and disruptive system of shared schools".
Roger Darlington, political adviser to Secretary of State Merlyn Rees, was especially scathing about the attitude of the hierarchy. He wrote: "The intellectual level of the arguments against shared schools mounted by the Armagh Three was pathetic...it needs to be explained to the Armagh Three that there is no question of compulsion. The intention was to provide the opportunity of shared schools only for those Catholics who wished to use them for their children. The Cardinal calls in aid Canon Law, but Catholic clergy outside Northern Ireland seem to be able to reconcile shared schools and Canon Law."
The overt hostility of the Catholic Church to integrated education meant that it was not necessary for those Protestants equally opposed, clergy and lay, to do anything. In the end the Labour government shrank from any attempt to set up shared schools. Returning to power in 1979, the Conservatives had other priorities.
Meanwhile, ACT built up its membership and campaigned and lobbied with remarkable vigour. On its behalf the Alliance peer, Lord Henry Dunleath, successfully sponsored enabling legislation in 1978.
The problem was that the legislation required clergy on governing bodies to take the initiative. This was not forthcoming. ACT would have to take action itself.
In 1981 came the great leap of faith with the establishment of what would become the flagship of the movement, Lagan College. It opened in Ardnavalley Scout Centre in south Belfast with 28 pupils in attendance.
Even with the generous support of charitable trusts, Lagan College had a hand-to-mouth existence as its pupil numbers grew. Some activists led by Tony Spencer, who were impatient to set up other integrated schools, broke away from ACT.
Their first school, Hazelwood in north Belfast, was in imminent danger of collapse when the newly-appointed education minister, Dr Brian Mawhinney, stepped in with vital aid. "If Hazelwood failed in a high-profile way,'' he wrote, "other parents would be discouraged from trying to start other integrated schools.'' In Mawhinney the integrated education movement had at last found a backer.
This Ulster-born MP for Cambridgeshire included in his 1989 Education Reform Order a statutory responsibility on the Department of Education to encourage and facilitate integrated education. With a bewildering array of initials and acronyms - including BELTIE, SUTIE and NAGIE - there were now many parent groups active in setting up integrated schools.
ACT was now only one of many players in the integrated education movement. But the members of ACT had been the trailblazers.
Their determination, tenacity and vision had been vital in setting in motion a movement which, by September 2009, would ensure that there would be over 20,000 pupils in 61 schools in every part of Northern Ireland.