On the same spot as Danny Morrison once exalted his party to think of taking power in Ireland with an Armalite in one hand and ballot paper in the other, Mr Adams declared: "The IRA's initiative was a brave one. To sue for peace is a noble thing."
The violence went on for so long the Republicans, like everyone else, could scarcely remember life without it. To begin with, Sinn Fein was little more than a legal flag of convenience for the IRA.
But throughout the 1980s the party developed into a substantial adjunct to the IRA until, at some stage, the tail started wagging the dog. Last year the Republican leadership decided, for a complex of factors, that a feasible alternative existed to the armed conflict and, in Mr Adams' words, sued for peace.
This Ard-Fheis represented an important step in the movement of Sinn Fein away from making up one half of a political-paramilitary double act towards more conventional politics. That transition has a fair way still to go.
The Republican leadership, headed by Mr Adams and Martin McGuinness, shows no sign whatever of resiling from the decision to go political. The IRA and the guns are still there, but there is no sign of them wanting to go back to the old ways.
But this is very much a transitional phase, and one message from the hall was that not everyone in the movement is so completely convinced that politics alone is the way ahead.
The attendance was the best for years and there were the usual rousing ovations for Mr Adams and Mr McGuinness, but there was also, for the first time since the ceasefire, public criticism of the peace process from within the movement.
Sinn Fein conferences are even more shamelessly stage-managed than those of the Conservative party and Saturday's main debate opened with no less than six consecutive speeches from leadership figures.
By the time they were through, the chairman was saying sorrowfully that, due to time pressures, other speakers could, alas, have only a minute and a half each. This was, however, time enough for the dissident voices to be heard.
Three Dublin delegates, one of whom works for Sinn Fein's own weekly paper, Republican News, stood up and said there was suspicion and concern about the peace process. One argued that the British government had not shifted on fundamentals and that the process would not lead to the British withdrawal they wanted.
Another said the danger was that Republicans would find themselves involved in a lengthy process which in the end would fall far short of their goal. A third said the strategy was damaging the "freedom struggle" and was a short cut which could not work.
The Republicans have always prided themselves that they, principally through the IRA, have in their language provided a dynamic for movement. The leadership is now in the business of arguing that Sinn Fein alone is capable of doing this as a major player now firmly at the centre of the political action.
The assertion is that this political action will lead inexorably towards eventually British disengagement. Applause for the dissidents, however, seemed to reveal a widespread fear that the process would not go so far.
"The British government still reaffirms the Unionist veto," said one. "Imagining or inventing conditions which don't exist is not a way forward," said another.
These are people who come from a culture accustomed to thinking in terms of eventual victory. At no stage did Mr Adams confidently promise them such victory: rather, he spoke of a search for agreement and a process of negotiations with no predetermined outcome.
He and the leadership have made their choice for the future, but not everyone in the ranks seems ready to regard the violence as a chapter definitively closed. He and the IRA have declared for peace, but it seems part of this profoundly militaristic movement still hankers after the old certainties of the gun and bomb, and doubts the wisdom of embarking with Mr Adams in his long march towards conventional politics.Reuse content