One by one, his rivals formed a handshake line behind the blocks at London Aquatics Centre and paid homage to Michael Phelps, the lord of the Olympic rings. In his racing finale on Saturday night, as a member of the United States men's 4x100-meter medley relay, Phelps collected his 22nd medal, and 18th gold.
Before Phelps retired, he had one last trophy to collect: a statuette that recognized his place in Olympic history and resembled a crinkled piece of aluminum foil from a foot-long sandwich.
"It's kind of weird looking at this and seeing 'Greatest Olympian of All Time,' " Phelps said, adding: "I finished my career the way I wanted to. I think that's pretty cool."
It sounds ludicrous now, but when Phelps, now 27, began his journey toward becoming the Tiger Woods of swimming, he had no clue what Mark Spitz had done. Unlike Woods — who kept a tally, like a to-do list, that included Jack Nicklaus's feats — Phelps was looking to the future when he put together the most ambitious Olympic program in the history of his sport.
Before becoming the first swimmer to race in eight Olympic events at the 2004 Games, Phelps was fuzzy on the details of Spitz's career. It was left to his coach, Bob Bowman, to fill him in on Spitz's seven-gold-medal performance at the 1972 Summer Olympics. Similarly, Phelps said that until recently, he did not know about the gymnast Larisa Latynina, who reigned for nearly five decades as the most decorated Olympian, with 18 medals.
Some architects of history work from a blueprint, while others, like Phelps, do not want to acknowledge any ceiling. Phelps transformed swimming, inspiring a generation at home and abroad, by building an audacious program out of grit, guts and a burning desire to make swimming cool for children all over the world.
"I wanted to change the sport and take it to another level," Phelps said.
On Saturday, Phelps followed Matt Grevers and Brendan Hansen in the medley relay, and 50.73 seconds later, he gave the anchor, Nathan Adrian, a lead that Adrian turned into a runaway victory over Japan and Australia.
The drama was in the details: the two cameras set up on either side of Phelps as he stepped to the blocks for his butterfly leg; the hugs with his teammates after the race; the tear-stained face of his mother, who stood with all the other fans applauding; and this conversation at the warm-up pool before the race, with Bowman, the Sherpa who took him to the sporting summit: "My tears are hidden behind goggles," Phelps told him. "Yours are streaming down your face."
Phelps's 22 medals are a mind-boggling total. If he were a country, he would rank in the top 60 in modern Olympic history. His 18 golds would put him No. 36, just ahead of Argentina.
The monarchy of Michael has loyal subjects far and wide, from Missy Franklin outside Denver to Chad Le Clos of Durban, South Africa.
Franklin, 17, who competed in seven events here, the most ever by a female Olympic swimmer, owes her ambition to Phelps, who made such a workload seem not only feasible but fun.
"He has done a world of difference for swimming," Franklin said. "He has really brought swimming onto the scene and gotten so many more people involved. Just what he's done is incredible, and he's kind of made people rethink the impossible — rethink what they can do and how they can push themselves."
She added: "I don't think his shoes will ever be filled. I think his footsteps are huge. Hopefully, I can make little paths next to his."
Le Clos, 20, said he watched Phelps win six golds and two bronzes at the Athens Olympics and was inspired to become a champion swimmer. It was not a coincidence that Le Clos swam six events in London, including the same four individual ones as Phelps. After watching Phelps win a record eight golds in Beijing, Le Clos added more events to his program to be like Mike. On Tuesday, he pulled off a monumental upset when he handed Phelps his first major international defeat in 10 years in the 200-meter butterfly.
"That's why I was so emotional afterwards," Le Clos said. "He was the reason I swam the butterfly. It's not a joke. If you think about it, it's kind of crazy." He added: "That's why I swim the 200 freestyle, both the I.M.'s. I don't swim it for any other reason than just because Michael does."
Phelps got choked up when he heard that he was Le Clos's hero and role model, Bowman said. "It means Michael's done what he wanted to do: affect the sport of swimming," Bowman added.
During the meet, Bowman said, a coach from another country approached him and said his swimmers had more of a public following because Phelps, making the sport more attractive to better athletes.
Just as Le Clos patterned himself after Phelps, there was someone whose career Phelps, or at least Bowman, studied carefully. Ian Thorpe of Australia won nine Olympic medals and became, in 2004, the first man to win medals in the 100-, 200- and 400-meter freestyles in a single Games. Thorpe's range extended to the 800 freestyle, an event in which he held the world record for more than four years.
Thorpe's versatility got the gears grinding in Bowman's mind. He sought out Thorpe's coach and spoke to him at length about what it took for Thorpe to consistently swim so many events so well. They talked about warm-ups and recovery and massage, elements that became part of Phelps's racing routine.
Bowman has since shared tips with Franklin's coach, Todd Schmitz, on maximizing performance in multiple events. It is because of Phelps that swimmers like Franklin think nothing of taking an ice bath to expedite their recovery.
Phelps has no peers in the annals of swimming, but is he the greatest Olympian ever? Sebastian Coe, a two-time Olympic champion in track and the chairman of the London Organizing Committee, said no. His argument was that swimming, unlike other sports, offers a smorgasbord of individual events and allows its athletes the opportunity to team up on relays, too.
That is true, but here is something to consider: to earn his 22 medals, Phelps had to race 46 times, counting preliminaries and semifinals, over three Olympics.
That is a lot of stress and strain. Ask James Magnussen, an Australian freestyle sprinter, who came into these Games as a gold medal favorite in the 50- and 100-meter freestyles. He failed to reach the final in the 50, missed the gold medal in the 100 by one-hundredth of a second, and led off the Australian 4x100 freestyle relay team that finished without a medal, in fourth.
"I have a lot more respect for guys like Michael Phelps who can come to the Olympics and back it up under that pressure," Magnussen said.
In the debate over history's greatest Olympian, Coe and other British sports enthusiasts may cast their votes for the rower Steve Redgrave, who won gold medals in five consecutive Olympics. But others, like the former Australian Olympian Susie O'Neill, will stump for Phelps.
"The Michael Phelps story is unbelievable," O'Neill, who won an Olympic medal of each hue in the 200 butterfly from 1992 to 2000, said in an interview with The Sunday Mail of Australia before the Games. "It's crazy he's going for three consecutive Olympic golds in four events."
No man had ever won the same individual swimming event in three consecutive Olympics. Phelps did it twice here in the span of 24 hours, with victories in the 200 individual medley and the 100 butterfly.
Among those he turned back in the butterfly final was Milorad Cavic of Serbia, who nearly outtouched him in 2008. "I cannot be compared to Michael Phelps," Cavic said. "I'm a one-trick pony. He does it all."
After the 100 butterfly on Friday night, Phelps wrapped his arm around Le Clos, who tied for second. In that moment, a mantle was passed.
"It's crazy to think he's retiring," Le Clos said, "because I've always looked up to him. It's going to be hard to go to a meet and he's not there."
Phelps will be gone but not forgotten. He inspired a generation, and more than all his medals, that is his greatest legacy.