Leicester City fans could be forgiven for still thinking the images of Andrea Bocelli belting out 'Nessun Dorma' on the King Power Stadium pitch and their heroes lifting the Premier League title were part of a wonderful dream.

Sports quiz aficionados of the future are likely to scratch their chins and rack their brains when trying to remember Wes Morgan as a title-winning captain.

Indeed, had any of these scenarios been presented as possibilities prior to the 2015-16 campaign, the orator of such suggestions would likely have had to contend with a fair amount of pointing, laughing and concerned looks.

And yet, despite pre-season odds of 5,000-1, Claudio Ranieri's cunning Foxes outlasted challenges from the Premier League's big hitters to complete a fairytale story that resonated throughout the world of football.

May 2 marks four years to the day since Leicester's moment of glory was confirmed after Tottenham's 2-2 draw with Chelsea, and to mark the occasion we have looked back at some of the most unlikely title triumphs in football history.

NOTTINGHAM FOREST 1977-78:

When Brian Clough took over at the City Ground in January 1975, Forest were languishing down in the old Second Division. A couple of years later Forest were promoted and under the stewardship of the maverick Clough they were crowned champions in their first season back in the top flight. Forest went on to win the European Cup in 1979 and 1980 in a golden era for the club.

HELLAS VERONA 1984-85:

In modern times Hellas Verona are known as a perennial yo-yo club, flitting between Serie A and B. But in the mid-80s, led by Osvaldo Bagnoli, they were top of a star-studded pile. In a league including Karl-Heinz Rummenigge (Inter), Michel Platini (Juventus) and Diego Maradona (Napoli), a well-crafted Verona side sat top of the pile in a shock considered one of the greatest in Italian football.

SAMPDORIA 1990-91:

Just six years on, and with Juventus, Napoli (twice), Milan and Inter each having won the title, there was another surprise in Italian football as Sampdoria became champions for the first time. Yugoslav coach Vujadin Boskov had already led Samp to two Coppa Italia successes and a European Cup Winners' Cup before a strikeforce of Gianluca Vialli and Roberto Mancini inspired the crowning glory. Arrigo Sacchi's memorable Milan side fell short, while an Inter team including Italia '90 World Cup winners Jurgen Klinsmann, Lothar Matthaus and Andreas Brehme were third.

DEPORTIVO LA CORUNA 1999-2000:

Barcelona and Real Madrid may presently have a stranglehold on LaLiga, but back in the 99-00 campaign it was Deportivo, a modest provincial club in the south-west of Spain, that rocked the apple cart - in part thanks to the financing of former president Augusto Cesar Lendoiro. A squad including Roy Makaay, Pauleta and Flavio Conceicao celebrated a famous LaLiga title.

WOLFSBURG 2008-09:

Bayern Munich have historically ruled the roost in the Bundesliga, yet there were five different winners in eight seasons between 2001-02 and 2008-09. The last of those saw Wolfsburg crowned champions for the first time in their history. A 5-0 rout at Hannover was followed by a 5-1 hammering of Werder Bremen in the final game of the season to emphatically complete the job, with Bayern two points back in second. The goalscoring exploits of Grafite (28) and Edin Dzeko (26) were crucial for Felix Magath's side.

AZ 2008-09:

Turns out 2008-09 was a year for upsets. AZ's own success story was described as "my little masterpiece" by Louis van Gaal, who had joined in 2005 after the pressure cooker of life as Barcelona coach. A 28-match unbeaten run was pivotal for AZ, who were champions for just the second time, as they romped to glory ahead of more illustrious names in Dutch football.

MONTPELLIER 2011-12:

Paris Saint-Germain are the modern powerhouses of Ligue 1, but it was a different story in 2011-12, PSG's first season under their wealthy Qatari owners. And rather than the capital giants triumphing, it was unfancied Montpellier celebrating an unlikely success. PSG invested for the future by bringing Carlo Ancelotti to the Parc des Princes in December 2011 and the likes of Kevin Gameiro, Javier Pastore and Jeremy Menez had arrived in the close season. But on the back of Olivier Giroud's 21 goals, Montpellier celebrated their first – and as yet only - top-flight triumph, finishing three points clear of PSG.

LEICESTER CITY 2015-16:

It was an achievement that forced ex-England striker and famous Foxes fan Gary Lineker to present the first episode of the following season's Match of the Day in his pants (albeit only brief-ly). With N'Golo Kante's tireless performances in midfield, Riyad Mahrez's wizardry on the wing and Jamie Vardy's scoring exploits, the Foxes lost just three times in an unforgettable season and finished 10 points clear of Arsenal in second. The usual challengers may have endured plenty of misery but nothing will ever take the shine off a remarkable achievement.