Lance Armstrong defied the odds to build a storied cycling career, then made a career of defiance as he steadfastly denied allegations that his unprecedented seven Tour de France titles were drug-aided.
Armstrong's announcement on Thursday that he would not seek to clear himself through arbitration of doping charges brought by the US Anti-Doping Agency marked a stunning change for a man who has never been afraid to tackle his detractors head-on.
For all of those detractors, there have been just as many admirers who point to Armstrong's own battle with life-threatening cancer and his charitable foundation dedicated to helping others living with the disease.
Doctors had given Armstrong a less than 50% chance of survival when he was diagnosed in 1996 with testicular cancer that had spread to his lungs and brain.
He persevered through surgery and chemotherapy and returned to cycling, but was little known in his homeland when he won his first Tour de France title in 1999.
His years of dominance in the sport's greatest race raised cycling's profile in America to new heights and gave him a platform to promote cancer awareness and research.
The Lance Armstrong Foundation has raised almost $500 million since it was created in 1997 and the foundation's chairman, Jeff Garvey, expressed support for Armstrong on Thursday as USADA vowed it would see him stripped of all seven of his Tour titles and banned from cycling.
"The leadership of the Lance Armstrong Foundation remain incredibly proud of our founder's achievements, both on and off the bike," Garvey said in a statement.
Even in the glory days, however, many were skeptical.
In 1999, it was a trace amount of a banned corticosteroid, with cycling officials saying he was authorized to use a small amount of cream containing the drug to treat saddle sores.
After his 2000 Tour triumph, French authorities probed his US Postal Service team but brought no charges.
Critics seized on his friendship with Italian doctor Michele Ferrari, who was banned by Italian authorities over doping in 2002.
In 2004, a Texas promotions company balked at paying him a $5 million bonus for his sixth tour title because of doping allegations by European media.
In that court case, former teammate Frankie Andreu and his wife, Betsy, testified that Armstrong told doctors during his cancer treatment that he had taken steroids and other performance-enhancers.
Two books published in Europe, "L.A. Confidential" and "L.A. Official," alleged he doped and in 2005 French newspaper L'Equipe reported that urine samples taken during the 1999 Tour that were re-tested later were positive for the blood-booster EPO.
Armstrong fought back with denials and even court action, but admitted after he retired in 2005 that he was weary of the onslaught.
In 2009, however, at the age of 37, he did launch a comeback, saying he wanted to use his renewed career to further promote cancer awareness.
Armstrong was still racing in 2010 as US authorities conducted an investigation into doping in cycling -- a probe that ended with no criminal charges but which apparently gave new impetus to USADA's probe.
His decision to forego arbitration -- after an unsuccessful bid to block USADA with a lawsuit -- will apparently see him go down in history as one of sport's most infamous drug cheats.
"If I thought for one moment that by participating in USADA's process, I could confront these allegations in a fair setting and - once and for all - put these charges to rest, I would jump at the chance," Armstrong said in a statement. "But I refuse to participate in a process that is so one-sided and unfair."