No legacy is so rich as honesty, at least not according to Shakespeare, and when it comes to sport the great bard was on to something.
After all, try scrolling through the list of athletics greats without disappearing down a rabbit hole of doubt, asking yourself not what they all achieved but how. Trust is hard-won when words mean so little, so the best gauge is usually actions.
For many, Mark Carroll will be remembered as a European champion, a waif of a kid from the wrong side of the tracks in Cork who grew up to run with the Africans, but one particular story about him, first heard many years ago from a clubmate of his at Leevale AC, should also be written into history.
It was the late 90s, a make-believe time in endurance sport, and the undetectable blood-boosting drug EPO was causing records to fall like autumn leaves. Carroll was one of the world's best distance runners at the time, gifted not with lightning speed but with an ability to sustain a searing pace.
As a result, he is approached by one a meeting promoter and made a highly lucrative offer to serve as pacemaker for an upcoming world record attempt. But Carroll, knowing the athlete in question, turns it down, telling him he wants no part of a dirty world record.
"That did happen," says Carroll. "I didn't believe the person was legit so I didn't pace the race and, sure enough, not too long after that same athlete got busted."
More than any drug test, athletes know what's real… and what's not.
"Sometimes you have to stick to your principles, man," says Carroll, his accent these days a curious blend of Irish-American. "If you're going to talk about doping then someone comes along and offers you bucks to pace a [doped] race, you can't turn around and do that.
"There were times you felt no matter how hard you ran it would never be good enough because some people were always going to take the easy route. At the end of the day, I can look back at my career and I know how I did it, but all the people who cheated have to look themselves in the mirror and figure out if they did the right thing."
Of course knowing what we do now, Carroll's achievements then have only risen in stock. Unlike those who made comical transformations late in their career, his ability was there from the outset: he was European junior 5000m champion in 1991, a world finalist at the age of 23, a European bronze medallist at 26 and European indoor champion at 28.
Fifteen years ago this weekend, Carroll tackled his first marathon in New York and finished sixth in 2:10:54, the second fastest ever by an Irishman.
"Sometimes ignorance is a good thing," he says of that race. "I respected the distance and the pain came, like it should, but I was able to plug on and get home."
He came home one place behind Italy's Stefano Baldini, who would go on to win Olympic gold in 2004, but by then Carroll's body was starting to wear. "New York was wonderful," he says. "I just wish I could have had more like that."
Probably the best race of Carroll's career, however, was when he set the Irish 3000m record of 7:30.36 in Monaco, which - believe me - will stand for decades. It's more than two seconds faster Mo Farah has ever run and is, essentially, the equivalent of running two four-minute miles back to back.
That was the one performance where, when I finished, I realised I'll never run faster ever again. I got on the train and hung on for dear life, but you have to be able to go through those layers of pain to run those times."
Such performances exist in a different realm to those of current Irish male distance runners, and no one has got within three minutes of Carroll's marathon time in the 15 years since. Last weekend the national title was won by 43-year-old Gary O'Hanlon in 2:18:52, while on the track, 5000m and 10,000m standards have fallen off a cliff.
Carroll has been based in the US for the past two decades, but he has his thoughts on the decline.
"There's a lot of very good coaches like Steven Macklin who are doing a very good job," he says. "The simple question is: are people training hard enough? I don't know how much kids are running nowadays, but are guys in the workforce getting out in the morning for their run and going again after? Distance running requires work, consistency, and we used to have no problem turning out 2:15 marathoners who worked full-time jobs."
Today Carroll lives in Des Moines, Iowa, where he was recently named director of track and field and cross country at Drake University. The end of his competitive career, like so many, occurred not by choice but a lack of options; his final years were spent battling pain from a twisted pelvis.
"I probably ran way past my expiration date," he says. "I always felt if I went to this doctor or that, I'd find something that was going to fix me. Giving up easy wasn't something I did, but you reach a point where you lose your contract, the financial squeeze comes and you realise it's time to move on, get a job and secure your future."
He began coaching some of Ireland's best distance runners like Gareth Turnbull, Mark Kenneally and Mark Christie, experience which helped secure work as head cross country coach at Auburn University in Alabama.
And while most in his position are radical in their support of the American scholarship system, Carroll is more cautious. "There are some athletes that should never leave Ireland if they can't truly commit to it," he says. "The athletes that do go, it's about trying to find the right fit academically and athletically."
Carroll's wife - Amy, a former elite distance runner - predicted he would struggle in retirement, such was his obsessive devotion, but instead he has flourished by channelling that drive into others.
"Coaching is not a job," says Carroll. "It's who you are. You have to be fully committed."
That was always his approach during his own career, sometimes to his detriment.
"You have to push your body very, very hard, and I did that, but I probably did it too much," he says. "As a youngster, I would never have dreamed I'd get to that level and run the times I did, but it took a lot of workouts and they hurt … a lot."
In retirement, he is a rare find: an elite athlete who appears content with his past, excited by the future.
"Barring injury and a few minor mistakes, I got the most out of myself," he says. "It's a good thing when you wake up in the morning, jump out of bed and have a spring in your step going to the office."
And while athletes today may - or may not - be facing a different landscape to Carroll, he has some critical advice for those who want follow his path to the highest echelons of the sport.
"There will always be people who take that shortcut," he says.
"But if you finish your career, know that you gave your best, raced your best and can look yourself in the mirror and know how you did it, that's ultimately what's important."
Ciarán Ó Lionáird has slammed Sport Ireland's anti-doping unit after it unsuccessfully attempted to test him yesterday morning, an infraction which may yet see the retired athlete fall foul of anti-doping rules.