The climax was strangely unremarkable: as footage emerged of the hotly awaited bilateral meeting between the US and Cuban presidents, it looked like any other sit-down on the sidelines of the summit. And in their comments before the assembled media they had words of caution. The process of rapprochement would take time. Patience was required. They would "agree to disagree" on some issues.
But speeches to their fellow leaders earlier in the day suggested the two men were serious about making history. And that meant moving on from history. As Obama put it, "The United States will not be imprisoned by the past."
This came with a jibe aimed at Ecuador's leftist president Rafael Correa, who had spoken beforehand with a tirade against America's legacy in the region. "I always enjoy the history that I receive when I’m here," Obama said. But he added, "I am the first one to acknowledge that America's application of concern around human rights has not always been consistent."
Raul Castro's speech followed, and at first it sounded like Obama would receive another history lesson. But midway through the speech, after passages spanning the Cuban War of Independence and the Revolution, suddenly there came an extraordinary moment.
Castro said he "apologized" to Obama for speaking about the revolutionary era with "such emotion." He explained that the much younger president bore no responsibility for what had gone before him - unlike Obama's predecessors, he was quick to add. But the point was unmistakable: like his American counterpart, Castro chose making history over dwelling on it.
What about democracy?
On the sidelines of the summit, Cuban dissidents had been invited to take part in a "Civil Society Forum." DW spoke to a democracy campaigner attending the Forum - Rosa Maria Paya, daughter of the prominent Cuban activist Oswaldo Paya, who was killed in a murky car crash in 2012. The Paya family accuses Cuban state security of causing the crash.
Rosa Maria Paya told DW that she greeted the efforts by the Obama administration and other regional governments to include Cuba. But she warned, "That inclusion cannot be complete until they, instead of just responding to the demands of the Cuban government, start responding to the demands of the Cuban people."
Paya says Washington should do that by backing a plebiscite on a transition to democracy. "While the Cuban people remain excluded, this transition process cannot start," she told DW.
The Obama administration is clear that it sees the rapprochement as being about more than Cuba. It wants to turn a page on relations with the whole region. In briefings ahead of the summit officials were not shy of invoking the president's "legacy" - something that will loom larger and larger as Obama approaches the end of his second term.
Some regional leaders seem receptive. Chile's foreign minister Heraldo Munoz told DW, "This is the beginning of the end of the Cold War in the region." His comments were echoed by Costa Rica’s foreign minister Manuel Gonzalez. He told DW, "We are very, very supportive of the process, not just at the bilateral level, but also as a region."
No more meddling?
Some of Obama's most striking comments on the US role in the region came at the Civil Society Summit. "The days in which our agenda in this hemisphere so often presumed that the United States could meddle with impunity, those days are past," he said. It appeared calculated to deflect criticism of his decision to impose sanctions on Venezuela just weeks before.
Washington cited human rights violations when it announced the sanctions in March, but it was widely criticized for providing embattled President Nicolas Maduro with a convenient distraction from Venezuela's economic and political problems - including his imprisonment of opposition leaders such as Leopoldo Lopez. Skeptics also asked why the Obama administration was wielding a stick against Venezuela while making so much of its carrot for Cuba.
Maduro and the sanctions
The sanctions led many to expect a major showdown with Maduro - an ally of the Castro regime. And sure enough, Maduro lashed out at the US in his plenary remarks, slamming the sanctions as an act of "aggression" and claiming to have amassed 11 million signatures demanding their revocation.
Ultimately, however, Maduro's speech was less virulent than many had expected. He demanded that Washington withdraw the sanctions - but quickly added that Obama was "no George W. Bush." It was an apparent acknowledgement of Castro's own warm remarks about the current president.
Later the White House confirmed that Obama and Maduro had a "brief conversation" on the sidelines of the plenary session. But Maduro did not get what he sought; the sanctions remained in place.
Obama also stopped short of granting Cuba what it has been demanding - its removal from the US list of state sponsors of terrorism. Officials say he is set to make a decision on that in the coming days.
Many had expected Obama to make the announcement at, or just before, the summit. But in public at least, Castro displayed no disappointment. He merely said he welcomed the fact that the decision would come soon.
Perhaps it was a sign that the Cuban leader meant what he said when he told his fellow Latin American leaders, "In my opinion, President Obama is an honest man," - and that he was confident their mutual decision to make history can no longer be undone.