If all five living United States presidents attend the state funeral service for former President George Bush on Wednesday, it will be one of a small number of times that this many of them have been in the same place at the same time.
There have been at least five of these rare gatherings since 1991.
In fact, there was only one period in United States history before then, around 1861, when more than five presidents were even alive at the same time.
Historians say the relative lack of transportation options would have made it exceptionally difficult for all but the most modern presidents to quickly convene. That, combined with longer life spans, has made meetings of five presidents more common — though still unusual — in recent years.
Here’s a look at a few of the occasions we know about, and the memorable moments that emerged.
Making history at Reagan Library
On Nov. 4, 1991, five United States presidents gathered on the same platform for what The New York Times reported was “the first time in history.”
The occasion? The dedication of the Ronald Reagan Presidential Library in Simi Valley, Calif. Along with George Bush, who was in office at the time, all the living former presidents attended: Richard M. Nixon, Gerald R. Ford, Jimmy Carter and Mr. Reagan.
In addition, six first ladies and several members of the Kennedy family were also present, allowing one official with the Ronald Reagan Foundation to call the event “the largest gathering of American presidents and presidential families ever assembled.”
Gathering to mourn Nixon
It was for a more somber occasion that five presidents came together on April 27, 1994. Mr. Nixon’s funeral was the first for an American head of state since Lyndon B. Johnson’s in 1973.
President Clinton, along with the four living former presidents — Mr. Ford, Mr. Carter, Mr. Reagan and Mr. Bush — attended. Mr. Clinton was among those who urged forgiveness for Mr. Nixon’s role in Watergate and Vietnam.
“May the day of judging President Nixon on anything less than his entire life and career come to a close,” he said.
The ceremony was held at the Richard Nixon Presidential Library and Museum in Yorba Linda, Calif. The word “Watergate” was never mentioned in the eulogies, benedictions and homilies, the Times reporter Maureen Dowd wrote.
Spiro T. Agnew, the former vice president who resigned in 1973 after pleading no contest to a charge of tax evasion, was among those in a conciliatory mood.
“I decided after 20 years of resentment to put it all aside,” Mr. Agnew said before the ceremony began.
Reagan ‘belongs to the ages now’
Ten years later, the presidents gathered to mourn another one of their own. This time, it was Mr. Reagan they assembled to remember at Washington National Cathedral.
On June 11, 2004, George W. Bush, who was in office, was the president delivering somber remarks.
“Ronald Reagan belongs to the ages now,” Mr. Bush told a gathering of nearly 4,000 mourners, which included all four living former presidents. “But we preferred it when he belonged to us.”
The Times reported that the cathedral’s bell tolled 40 times in honor of Mr. Reagan’s place in history — he was the country’s 40th president — and then the procession began its journey across the country to California, where mourners gathered at his presidential library for a service and interment.
George W. Bush gets his day
Five presidents found themselves together again on April 25, 2013 — this time for the dedication of the George W. Bush Presidential Library and Museum in Dallas.
It was a day to celebrate Mr. Bush, and President Obama — along with Mr. Carter, Mr. Clinton and the elder Mr. Bush — took turns offering their praise.
Mr. Clinton — who by then had attended other presidential library dedications, including one for himself — said, “This was the latest, grandest example of the eternal struggle of former presidents to rewrite history.”
For his part, Mr. Bush told the crowd of thousands “that people can disagree.”
“It’s fair to say I created plenty of opportunities to exercise that right,” he said. “But when future generations come to this library and study this administration, they’re going to find out that we stayed true to our convictions.”
Unity for hurricane relief
In an increasingly rare show of political unity, the five living former presidents appeared on another Texas stage together last fall to help raise money for hurricane recovery efforts.
The public show of unity at the “Deep From the Heart” concert was part of a larger disaster relief campaign in the wake of hurricanes Harvey, Irma and Maria.
President Trump also made an appearance of sorts at the benefit on Oct. 21, 2017 — but it was on a prerecorded video.
“This wonderful effort reminds us that we truly are one nation, under God, all unified by our values and our devotion to one another,” he said.
Bonus: A special meeting in the Oval Office
O.K. We know he wasn’t president yet, but just days before Barack Obama was sworn in, he met with President George W. Bush and three of his predecessors on Jan. 7, 2009, in the Oval Office for what Mr. Obama called an “extraordinary gathering.”
“All the gentlemen here understand both the pressures and possibilities of this office, and for me to have the opportunity to get advice, good counsel and fellowship with these individuals is extraordinary and I’m very grateful to all of them,” he said, adding praise for Mr. Bush for hosting.
We won’t count this as one of the five meetings, but we thought you should know. (And the picture was nice.)