Max Mosley, the former president of motorsport's world governing body the FIA, who has died aged 81, "was like a brother", ex-Formula One supremo Bernie Ecclestone told AFP.
Mosley became FIA president in 1993 after serving in previous administrative roles in the sport, including within Formula One.
The former racing driver, who had been suffering from cancer, served three terms as president before standing down in 2009.
"We were I suppose like brothers," Ecclestone told AFP by phone from his base in Switzerland.
"Max could be a difficult person to understand but we understood each other.
"I could tell him if I felt he was wrong and he would accept it and he could do vice versa."
Ecclestone, 90, said Mosley did not get the credit for what he had done in the sport.
"He was interesting and a character," said Ecclestone.
"He had a Corinthian spirit.
"He was the sort of guy who was hard to get to know.
"Those who did not know what he was really made of found it easier to criticise him than try and get to know what made him tick.
"Thus they would rather remember him making one mistake than for all the good he did."
Ecclestone said Mosley having been a driver had the best interests of the sport at heart.
"He was genuinely interested in doing what he could to make the sport more accessible and easier for people.
"Personally I think they were pretty good changes."
Mosley was the son of 1930s British fascist leader Oswald Mosley and Diana, one of the famed Mitford sisters.
He found, though, that his colourful parentage was not a problem when he drove in Formula Two for Brabham in 1968.
"I heard somebody (one of his fellow drivers) say, 'Mosley, Max Mosley, he must be some relation of Alf Mosley, the coachbuilder.'" Mosley recalled to Atlas F1 in 2011.
"And I thought to myself, 'I've found a world where they don't know about Oswald Mosley.'"
In 2008 he won a privacy case against the now-defunct News of the World newspaper after it printed photographs and published video of his involvement in a sadomasochistic sex session.
It was reported by the newspaper as a "sick Nazi orgy" but the judge found no evidence of Nazi themes in his judgement.
He also said there was no public interest defence in the clandestine recording of the session.
- 'This is trouble' -
Mosley experienced a family tragedy in 2009 when his son Alexander died aged 39. The coroner ruled Alexander's death was due to non-dependent drug abuse.
Mosley senior studied at Oxford University, where he read physics, but later trained as a lawyer and became a barrister whose specialism was patent and trademark law.
His love of motor racing began in his youth and he was involved in Formula 2 for Brabham and Lotus before retiring in 1969.
His first race at the Nurburgring in Germany in 1968 is best known for the tragic death of legend Jim Clark.
A year later at the same track an accident prompted him to call time on his career.
"The left front wheel stopped turning and I thought, 'This is trouble', and I ended up in the caravan park," he told Atlas F1 in the 2011 interview.
"It was evident that I wasn't going to be world champion."
He became president of FISA, Formula One's governing body at the time, in 1991 and two years later took over unopposed at the FIA.
He oversaw the safety reforms in the sport that followed the death of Ayrton Senna at the San Marino Grand Prix in 1994.
Jean Todt replaced Mosley as FIA president in 2009. Since then, Mosley had campaigned for tougher regulation of the press.
The Williams Racing team were one of the first to pay tribute, tweeting from their official account: "We are saddened to learn of the passing of former FIA president, Max Mosley.
"Our condolences go out to his family and friends at this difficult time."