Football has seen plenty of influential characters. There have been many players and managers who have left a mark on the game, but few will ever match the significant of the great Sir Bobby Robson.
A solid, unspectacular forward during his playing days, Robson took his reputation to new heights when he turned Ipswich Town into a genuine powerhouse during the 1970s, but that was just the start of perhaps the most influential managerial career of the last century.
While his eight years with England might seem more important on paper, Robson single-handedly changed the future of football in July 1992, when he headed over to Portugal to take charge of Sporting CP.
Given he didn't know a word of Portuguese, Robson needed help from a plucky upstart by the name of Jose Mourinho, with whom he built up a close relationship and eventually invited to become his assistant manager when he moved to Porto in 1994.
"What did he give me? I couldn't describe by words, and I wouldn't go in the football direction," Mourinho told Sky Sports News in 2019. "It's incredible what he means to the people and for me it's hard to speak about him."
Joining the fun at Porto was a 16-year-old Andre Villas-Boas, who joined the scouting team and was eventually helped through his coaching badges at the tender age of 17.
Robson was already building up an illustrious team of future stars, showcasing his unrivalled eye for backroom talent and using his gentle, nurturing personality to give these young soon-to-be's the kind of education that would see them become two of the biggest names in the game in just a few years.
However, that influence would soon step up when Robson and Mourinho took over at Barcelona in 1996, managing a side that included future world champion Pep Guardiola.
Fast-forward to March 12, 1997, and Robson was facing the sack at Camp Nou. Both his and Mourinho's careers were on the line as Barcelona went 3-0 down to Atletico Madrid in the first half of a Copa del Rey tie. Robson looked done, and his eventual replacement, Louis van Gaal, was already in attendance. Barcelona were certain Robson was cooked.
Robson's half-time team talk may well be the most important moment in recent football memory.
The Englishman helped rebuild his side's confidence and brought in a tactical switch with led to Barcelona firing home five goals in the second half.
Robson kept his job, Mourinho's credibility was intact, but in another twist of fate, the boss' actions helped convince Guardiola that he wanted to become a manager once he hung his boots up.
"I learned a lot," Guardiola said during the film of Robson's career, Bobby Robson: More Than A Manager. "I thought, 'I want to become a manager,' because of how he handled that situation. It was incredible. It doesn't matter what the media says, everyone trying to push you: always try to be calm."
Robson retired from management in 2004, when he got to kick back and reap the rewards of all his hard work.
He watched Mourinho lead Porto to Champions League glory in 2004, before lifting two Premier League titles with Chelsea between 2004 and 2006. Robson even managed to catch Mourinho leading Inter to the Serie A title in 2009 before tragically losing his battle with lung cancer that summer.
However, while his death was obviously devastating, it came at such a storybook moment. Robson lived long enough to see Guardiola win La Liga, the Copa del Rey and the Champions League in his first year as Barcelona manager. His work was done.
Robson knew that he had played a major role in sculpting the careers of these two future greats, but he never learned the full extent of his impact.
It's almost hard to comprehend the number of trophies Robson did not get to see his disciples lift. Mourinho has added 11 major honours across three different countries since Robson's passing. Guardiola has brought in 26. Luis Enrique, part of his Barcelona team, won nine at Camp Nou. Even Villas-Boas has lifted seven across Portugal and Russia.
Without Robson, some of the greatest memories of the last 20 years may never have happened. Football today looks like it does because of him, and few people will ever have the honour of saying that.