VIENNA — On Saturday morning in Vienna, on a course specially chosen for speed, in an athletic spectacle of historic proportions, Eliud Kipchoge of Kenya ran 26.2 miles in a once-inconceivable time of 1 hour 59 minutes 40 seconds.
In becoming the first person to cover the marathon distance in less than two hours, Kipchoge, 34, achieved a sports milestone granted almost mythical status in the running world, breaking through a temporal barrier that many would have deemed untouchable only a few years ago.
Still, the eye-popping time will not be officially recognized as a world record because it was not run under open marathon conditions and because it featured a dense rotation of Olympic pacesetters.
What the event lacked in officially sanctioned gravitas it seemed determined to make up for with theater and grandiose proclamations.
The run, organized by the petrochemical company INEOS, featured a cycle of hype and commercial buildup more reminiscent of a heavyweight prizefight than a road race.
Organizers billed the two-hour mark as “the last barrier of modern athletics” and tried to get a hashtag, #nohumanislimited, trending on social media.
Kipchoge, the winner of eight major marathons and three Olympic medals, repeatedly compared a potential sub-two-hour marathon to humanity’s first journey onto the surface of the moon.
Whatever the scope of the achievement, it required a prodigious amount of planning.
Seeking the most welcoming environment to attempt such a feat, the event’s organizers settled on Vienna: It was not too warm, not too cold and not at all hilly.
It is also only one time zone away from Kipchoge’s training camp in Kaptagat, Kenya, where he had worked out for the past four months under the guidance of his longtime coach, Patrick Sang.
Kipchoge had made an attempt at the two-hour barrier once before. In 2017, in a similar event organized by Nike, he ran a 2:00:25 marathon around an auto racetrack in Monza, Italy. It was by far the fastest marathon ever run, but it was not officially recognized as a world record because it was not run under normal race conditions.
Since then, and in officially sanctioned major marathons, Kipchoge has produced the two fastest times in history, posting a world-record time of 2:01:39 in Berlin in 2018 and 2:02:37 last April in London.
“Berlin was about running a world record,” Kipchoge said this week. “Vienna is about running and breaking history, like the first man on the moon.”
Altering his preparations since the sub-two-hour attempt in Italy, Kipchoge added to his program more workouts focused on core strength in order to lessen the strain on his hamstrings.
He arrived in Austria on Tuesday, but the exact start date for the attempt was not finalized until the following day, and the precise start time was not settled until Friday afternoon.
The organizers said they were seeking the optimal conditions to run. Nothing would be left to chance.
On Saturday morning, at 8:15 a.m., Kipchoge set out from the Reichsbrücke, a picturesque bridge spanning the Danube. He ran behind a timing car driving 4:34 per mile (with a second car on standby) and with a flock of rotating pacesetters (35 on the course, with six on reserve) who happened to include some of the best distance runners in the world, including former world and Olympic gold medalists like Bernard Lagat and Matthew Centrowitz.
Kipchoge and his accompanying men and machines charged around a 9.6-kilometer flat circuit mapped out through the heart of Vienna’s Prater Park. More than 90 percent of the course unfurled in a straight line, and portions were painted with lines on the road to highlight the fastest possible path.
A little less than two hours later, he crossed the finish line in unprecedented time — albeit not one that would be recognized in the record books.