It's the age-old argument: Who is the best player?
The most modern take on it involves only two players in all honesty, but in days gone by, it might have involved far more.
The "greatest ever" tag is generally awarded on favouritism, patriotism or a bias because of results against a favoured team. It's also at times something of a misnomer, given the disparity between different eras of the game.
But we can always compare players from the same time, the same game, the same decade.
Though the rules of football as we know it were devised in 1848, it wasn't until the 1920s when the game was recognisable as it is today, with several important rule changes, including goalkeepers not being allowed to handle outside the area and the 10-yard rule for players defending free kicks coming into effect.
As a result, no players from before that era have been considered for inclusion in this collection of greats.
Here are the greatest players, one from each decade, from the 1920s to now.
When a goalkeeper performs so well over an extended period of time that a century later a trophy is still handed out with his name attached to it, you know that the talent has been of an exceptional standard.
Ricardo Zamora was Spain's greatest goalkeeper ever for a time and perhaps even still is.
Having started out as a youngster with Espanyol, he spent three seasons with Barcelona, despite his parents preferring him to join them in the medical profession, before enjoying an extended spell back at Espanyol and finishing up his career with Real Madrid.
Zamora won two league titles, five Spanish cups and an Olympic silver medal, along with 46 Spanish national team caps.
To this day, the award handed out in La Liga at the end of the season to the best goalkeeper is the Zamora Trophy. This goes to the 'keeper with the best goals-conceded coefficient; the most recent holder being Victor Valdes for the past four seasons.
Like Zamora from the decade previous, the star of the 1930s has his name etched into the modern-day world of football, this time in a stadium name.
Giuseppe Meazza is the name, and the stadium dedicated to his honour and memory is that of AC and Inter Milan in Italy.
Meazza was a showman, a match-winner and a footballing genius who remains Internazionale's highest all-time goal scorer, with 287 strikes to his name.
He won two World Cups as he claimed more than 50 caps for his country and added three Italian championships to his collection.
Playing either as an out-and-out striker or an attacking midfielder, as he did for his country in the first of his World Cup appearances, Giuseppe Meazza proved a true great of the game with his dribbling ability, trickery and composure.
After spending more than a decade with Inter, Meazza also appeared for AC Milan for two years.
Fans in England in the 1940s were blessed to watch two of the finest players around at the time in Tom Finney and Stanley Matthews.
Finney arguably reached his very peak during the following decade, while Matthews graced the game for no less than 33 years at the professional level—his last top-flight appearance came after his 50th birthday, a phenomenal achievement.
Stanley Matthews played almost 800 games during his career and was never booked a single time.
Great pace, tremendous dribbling and over 50 caps for his country made him a true legend of the game.
The 1950s saw an explosion of talent, or at least much more of it was brought to the attention of the world at large.
From John Charles at Leeds to Fritz Walter at Kaiserslautern, players from around Europe showcased their abilities and laid claim to the title of best in the world.
No 50s list would be complete without a mention of Just Fontaine of course, but in truth there was a superpower at this time and they played in Spain.
Real Madrid won four league titles and four consecutive European Cups during the decade as they dominated the landscape of football, and though they had other star players—Francisco Gento being one—it was Alfredo Di Stefano who rightly should be acknowledged as the best of the 50s.
Di Stefano played in all of those trophy wins and netted over 300 times for Real Madrid.
Curiously, he also played international football for three countries during his career—though only for Spain during the 1950s.
If the 50s were special, then the 1960s were nothing short of mind-blowing in terms of football talent around the globe.
From the legendary Russian goalkeeper Lev Yashin through to Manchester United's Bobby Charlton and George Best, the Brazilian Garrincha and the Portuguese striker Eusebio, truly there were some timeless players in this generation whose feats will be remembered for decades yet to come.
Inter Milan's attacking full-back, Giacinto Facchetti, one of the first and finest in the game, should not be overlooked also.
Undoubtedly there will be those who champion Pele, one of the finest players of the game ever, as the best of this decade.
But there was a greater player than Pele in this era—Ferenc Puskas, the legendary Hungarian, one of the "Magical Magyars."
Puskas shone as he led his national team to the World Cup final, where they lost in 1954.
It was in the 60s though, when Puskas enjoyed arguably his finest moments and certainly the most successful spell of his career, despite being more than 30 years of age when he joined Real Madrid.
He hit four goals in the 7-3 thrashing of Eintracht Frankfurt in the 1960 European Cup final—Real's fifth consecutive triumph—and went on to win five league titles with the club in the years that followed.
Puskas was one of the greatest four or five players to have ever played the game of football and perhaps would be more roundly regarded as so had he been of a different nationality, or had his Hungary team ended successfully in 1954.
The 1970s had its fair share of top-class talent, but one man stands firmly above them all: Johan Cruyff.
Hugo Sanchez, Teofilo Cubillas, Falcao, Rivelino, Ruud Krol and the Bayern Munich duo Sepp Maier and Franz Beckenbauer were all true greats, but none come close to eclipsing Cruyff.
Having spent his formative years making himself a worldwide phenomenon with Ajax, Cruyff moved to Barcelona in 1973, where he went on to win a Copa del Rey and a Spanish league title, having already won a hat-trick of European Cups with his former club.
Cruyff was one of the most respected players of the Dutch "Total Football" era under Rinus Michels and was an elegant, visionary player who was capable of achieving on the field of play that which others wouldn't even dream about.
He is a three-time European Footballer of the Year.
Much like the previous decade, there were a whole host of outrageously talented footballers on display in the 1980s—but all of them were eclipsed by a true genius, a once-in-a-generation talent who perhaps remains the greatest individual the game has ever seen.
Diego Maradona played for Boca Juniors and Barcelona but it was at Napoli that perhaps his greatest talents were on display most regularly—as well as for his national team of Argentina, of course.
Maradona won a UEFA Cup and two Italian league championships with Napoli, but will be forever remembered for his incredible displays at the 1986 World Cup in Mexico, which he had a huge hand in Argentina winning.
Diego's legendary "Goal of the Century" was widely regarded as the greatest of all time, and for many people still is because of the occasion as much as the skill it took.
It still behooves us to at least give a cursory nod to those who, though they reached not the majestic heights which the man who brought us "the Hand of God" attained, were certainly standout players in their respective leagues and the game at large.
Michel Platini was one of the game's greats, as was Karl-Heinz Rummenigge for Bayern Munich and his teammate Lothar Matthaus. In Italy, Zbigniew Boniek was perhaps the greatest Polish player ever and plied his trade at Juventus in his prime, while Kenny Dalglish of Liverpool and Zico at Flamengo were also truly amongst the greatest players in the world.
Franco Baresi and Dino Zoff make up just a handful of these other memorable players.
While the rest of Europe and South America have contributed players to each decade up until now, many of the very best of the footballing world resided firmly in Italy for much of the 1990s.
Serie A was the top flight for entertaining, quality football, and the fact that Italian sides made up nine of the European Cup finalists between '89 and '98 was testament to this.
In fact, the 1991 final was the only one in this period of time which did not contain a side from Italy.
Paolo Maldini and Marcel Desailly held sway for AC Milan, while Roberto Baggio dazzled everybody at Juventus, AC Milan and Bologna for a time. George Weah was another who made the majestic seem easy at times, though perhaps not with the consistency that others achieved.
Outside of Italy, Abedi Pele and Peter Schmeichel were legends in their own right, and Ronaldo perhaps was at his most devastating while playing for PSV and Barcelona in this period before his move to Inter Milan and the beginnings of his injury problems.
One more bears mentioning before we move on to the greatest of the decade: Zinedine Zidane began his rise late in this decade to become one of the best in the world from any time period.
The 1990s though belonged to Michael Laudrup, the Danish attacking midfielder playing at both Real Madrid and Barcelona.
The great Franz Beckenbauer even stated how highly he rated Laudrup, comparing him to greats of the years gone past.
Laudrup might have missed out on European Championships glory with his country in 1992 but he still collected a European Cup, an Italian league title, five league titles in Spain, another in Holland and won over a century of caps during his magnificent career.
The Danish playmaker maybe showed his best abilities at Barcelona but still had plenty left to give to rivals Real Madrid, whom he directly transferred to in 1994.
Zinedine Zidane at Real Madrid—there has been perhaps no finer exponent of playing the game of football to the absolute highest level without the need for breakneck speed.
Zidane moved from Juventus to Real in 2001 and, in his five years in Spain, picked up a haul of medals including a Champions League, a Spanish league title and another FIFA World Player of the Year award—his third overall.
Incredible poise, vision, accuracy of passing and sublime control made Zidane peerless in the most recently passed decade, with perhaps only Ronaldinho of Barcelona able to even closely compare to him.
The French midfielder also won a European championship while he was with Real to go alongside the World Cup he won in 1998—but his career ended on a less-than-perfect note when, in the 2006 World Cup, he was sent off in the final instead of winning it.
There are only two candidates for this particular fledgling decade: Cristiano Ronaldo and Leo Messi.
And it isn't even a particularly close decision.
The two are the standout players in the most modern version of the game, athletically a world apart from the likes of Puskas or Fontaine.
In terms of pure talent, though, Messi stands head and shoulders above anybody else, and given he is yet just 25 years of age he seems set to go on and dominate the rest of the 2010s.
Playing in a fantastic team he has already won five league titles and three Champions Leagues, is a three-time winner of the Ballon d'Or, is the all-time leading goalscorer for Barcelona and is chasing down the all-time world record of scoring the most goals during one calendar year.
That currently stands at 85, held by Gerd Muller—Messi so far has 82, and several games to play in December.
He's undoubtedly the star of the present decade.