Britain's Fred Perry was the first man to achieve a career Grand Slam, back in the days when tennis was mainly an amateur sport and the men often played lengthy tours against a specific opponent.
Perry – also a champion table tennis player - was 18 when he took up the tennis, yet less than eight years later had won each of the Grand Slams at least once, and had already spent the first of four years as the world number one.
Like Federer, Perry's last Grand Slam title came at the French Open, with a four-set victory over defending champion Gottfried von Cramm in 1935.
Three years after Perry won the first career Grand Slam, his American arch-rival Don Budge emulated the feat. Budge, considered to have the best backhand in the history of tennis, also completed his career Grand Slam at the French Open before going on to win all four Majors in a calendar year - the first man to achieve such a feat.
The outbreak of the Second World War forced many tennis players into the armed forces and resulted in the suspension of Grand Slam events. The US Open continued as before and the French Open missed just one year, but the Australian Open and Wimbledon disappeared for the duration of the war and it was nearly 30 years before anyone dominated in the same fashion as Perry and Budge.
But when those players did emerge, the word 'domination' hardly seems adequate to describe their success.
Australians Rod Laver and Roy Emerson shared the Australian Open title (then the Australian Championships) for eight straight years and contested five other Grand Slam finals.
Laver was arguably the better and provides the closest competition to Federer for the mantle of the greatest the game has seen.
With his first Grand Slam title coming at the 1960 Australian Open, Laver had completed a career Grand Slam by 1962 and went on to repeat the feat by 1969.
Yet despite winning eight Slams in those two years alone, the Aussie collected only 11 Grand Slams in total.
The reason for this is clear. The top-tier tennis championships were still amateur events for most of the 60s, and when Laver turned professional after his amazing 1962 season he was barred from competing at any of the four.
In 1968, though, the open era began as tournaments opened their doors to professionals.
How many Grand Slam titles would the Australian have won had he been allowed to compete between 1963 and 1967? It's impossible to say. Comparing eras is always difficult, but it seems safe to assume that Laver would have ended up with considerably more than the record 14 shared by Pete Sampras and Federer.
Unlike Laver, Emerson did not turn professional, which allowed him to win more major titles that his compatriot.
Emmo, as he was known on tour, did not take long to secure his career Grand Slam, completing the feat at Wimbledon in 1964. He also held the career record of 12 Grand Slam victories - among them six Australian Open titles - for 34 years, until it was surpassed in 2000 by Sampras.
Emerson is also the only male player to have won all four Grand Slam singles and doubles titles.
Admirable as all these achievements are, there is one crucial thing that leaves Federer heading the list for the game's greatest player: the fact that until 1987 the Australian Open was played on grass.
Hence Perry, Budge, Laver and Emerson won on three different surfaces only, which adds to the argument that Federer's diversity makes him more impressive.
Only one other male player can claim to have won all four Majors on four surfaces, and that is Andre Agassi (pictured, right).
The American completed his career Grand Slam at the 1999 French Open, seven years after first winning at Wimbledon. Agassi went on to win the last of his eight Major titles at the Australian Open in 2003, before crawling into retirement three years later at the grand old age of 36.
Federer (pictured, left) could have completed his career Grand Slam as early as 2006, when he reached the first of his four French Open finals.
But Rafael Nadal stood in his way, as he did again in 2007 and 2008.
So, does the fact that Federer has not won all four Majors in a year dent his claim? Probably not, as he reached all four finals in both 2006 and 2007, with only the French Open title eluding him on both occasions.
That record puts even Sampras in the shade. For all his skills, the American never reached the same level of consistency as the Swiss. He was never able to win more than two Majors in a calendar year, something Federer has managed twice.
Did the fact that Federer did not have to beat Nadal on his way to this year's French Open title make it an easier win? In a word, no. Nadal is an outstanding clay court player, but Federer beat the Spaniard just three weeks ago in the Madrid Masters with a performance just as outstanding as the one Robin Soderling produced to consign Nada; to his first defeat at Roland Garros.
Doubters will always find a reason not to proclaim Federer the greatest player to grace a tennis court, but one thing is for sure: time and again Federer has beaten the opposition put in front of him.
And this is far from the end of his story. With a record-equalling 14 Grand Slam titles across all the surfaces in just six years, the 27-year-old potentially has another five or six years of peak tennis left in him yet.
Just ask Agassi.