Chelsea first won a top-flight league title in 1955, with manager Ted Drake delivering success with signings from smaller clubs in the lower leagues.
When the Blues won the Premier League 50 years later, they did so with a far more cosmopolitan and expensive group of players led by Portuguese coach Jose Mourinho.
The Roman Abramovich takeover in 2003 changed Chelsea forever, as it allowed them to spend millions of pounds on overseas stars, transforming them into the European powerhouse that they are today.
However, the west London club had a history of canny transfers before that which is also worth celebrating.
As a result, Goal looks at Chelsea top 15 greatest ever signings, with players ranging from the first ever title win to the present-day champions.
FRANK LAMPARD | From West Ham | £11m | 2001
Frank Lampard's name is still sung at Stamford Bridge, three years after he left the club in 2014. It is, thus, funny to think that some pundits felt that Chelsea had overpaid when they signed the midfielder from West Ham in 2001 for £11m.
However, Lampard went on to become the club's highest ever goalscorer, with 211 strikes during 13 years at Stamford Bridge, and his greatest moment in a Blues shirt might well be the brace he scored away to Bolton Wanderers in 2005 to seal the club's first title win in 50 years.
In total, the former England international won 11 major honours at Chelsea before departing for Manchester City.
DIDIER DROGBA | From Marseille | £24m | 2004
Didier Drogba is the king of Stamford Bridge due his remarkable achievements as part of the greatest group in the club's history.
Most memorably of all, he scored an 88th-minute equaliser in the 2012 Champions League final against Bayern Munich to keep Chelsea's dream of a first European Cup triumph alive, before then going on to convert the winning spot-kick in the penalty shootout.
Unsurprisingly, the Ivorian, who ranks fourth on the club's all-time goal-scorers list, was voted the club's greatest ever player in 2012 in a poll of 20,000 fans.
He left in a pioneering move to play football in China but Jose Mourinho brought him back in 2014 on a free transfer and Drogba added a League Cup and another Premier League title to his trophy haul to make it 12 major honours in his time at Chelsea.
EDEN HAZARD | From Lille | £32m | 2012
Eden Hazard was the world's most sought after player when he moved to Chelsea from Lille in 2012 for £32m. He announced "I'm signing for the [this season's] Champions League winner" on Twitter, as Chelsea capitalised on their win with a major signing.
Joe Cole, who narrowly misses out on this list, thinks that Hazard could go down as Chelsea's greatest ever player if he stays at the club - and he's right. If Hazard does leave, the club will make a huge profit on their initial £32m outlay, with the winger having inspired the Blues to two Premier League titles in the past three seasons.
PETR CECH | From Rennes | £7m | 2004
Thibaut Courtois may surpass Petr Cech as the club's greatest ever goalkeeper but that day hasn't arrived just yet. The Czech wasn't cheap, as he arrived from Rennes for £7m, meaning he was, at the time, the most expensive goalkeeper in the club's history.
He proved himself worth every penny as he won every major honour in his 11-year spell at the club. He was involved in the greatest moment in the club's history, too, as Chelsea became the first London club to lift the Champions League.
He was a giant in the 2012 final against Bayern Munich, saving Arjen Robben's penalty in extra-time before then stopping two more spot-kicks in the shootout.
CLAUDE MAKELELE | From Real Madrid | £16.8m | 2003
No other player in this list influenced football so much that they had a position named after them but Claude Makelele is the man responsible for redefining the role of the defensive midfielder.
Fernando Hierro described the Frenchman leaving Real Madrid for Chelsea as "the end of Los Galacticos", as the former Blancos ace knew the importance of Makelele's work to the rest of the team, so it was no coincidence that his arrival heralded the start of a new era of success at Stamford Bridge.
Claudio Ranieri may have signed Makelele but it was Mourinho who used him to drive the club to English football domination. Makelele won five major honours in his time at Chelsea and he deserves to go down as a club legend.
MARCEL DESAILLY | From AC Milan | £4.6m | 1998
Marcel Desailly was a surprise signing when he joined Chelsea from AC Milan in a £4.6m deal. The legendary French defender arrived at the club as World Cup and Champions League winner.
He went on to win Euro 2000 with his country but only one major honour in his six-year spell at Stamford Bridge but he is often cited as a major influence on the emerging John Terry, which could be his greatest legacy of all.
GIANFRANCO ZOLA | From Parma | £4.5m | 1996
In 2003, ahead of Roman Abramovich's takeover, Gianfranco Zola was voted the club's greatest player and he holds a unique place in the hearts of Chelsea fans.
He was just as loved by the press, though, as underlined by the fact that the Italian was the first Blues player to win the Football Writers' Association Player of the Year award, in 1996–97.
The former Parma ace also won five major honours with Chelsea, including the Cup Winners' Cup, and he was the star man within a group of exciting players that first attracted Abramovich to invest in the west London club.
MICHAEL BALLACK | From Bayern Munich | Free | 2006
Michael Ballack makes the list not only because he made a big impact at Stamford Bridge but also because he cost nothing! Chelsea beat Manchester United to the signature of the Germany midfielder to secure one of the greatest free transfers of all time.
Bayern Munich wanted to keep their star man but he chose the Premier League and he was inspired by the Roman Abramovich era group - as well as the lucrative wages on offer.
He went onto win five major honours for Chelsea in his four-year spell in England and although he was generally behind Frank Lampard in the pecking order, he is fondly remembered by Blues fans.
WILLIAM GALLAS | From Marseille | £6.2m | 2001
William Gallas played for both Arsenal and Tottenham but his best years were with Chelsea. The Frenchman partnered John Terry and Marcel Desailly at centre-back but he was also an excellent full-back and was part of the transition into the Roman Abramovich era.
Alongside Terry, Gallas went 16 games without conceding a goal before winning back-to-back titles under Jose Mourinho.
ASHLEY COLE | From ARSENAL | £5.5m + Gallas | 2006
Gallas was ultimately sacrificed to bring in long-term Chelsea target Ashley Cole. The former Arsenal man was a world class left-back at the peak of his considerable powers and he might go down as the greatest that England has ever had.
A protracted transfer saga, which was plagued with controversies, eventually ended with Chelsea securing Cole in a £5m plus Gallas deal from Arsenal. It proved a bargain, as Cole helped Chelsea win the Champions League, as well as every major honour during his time at the club.
He had eight glorious years at the club and the Blues have never found anyone as good as him since he left.
ARJEN ROBBEN | From PSV EINDHOVEN | £12.1m | 2004
Arjen Robben was pivotal in Chelsea's back-to-back title wins during Mourinho's first spell at the club. He provided goals and assists as well as being an excellent outlet for the defensively sound side.
Robben rejected Manchester United to move to Chelsea from PSV Eindhoven and he spent three years at Stamford Bridge before the Blues made a tidy profit on the Dutchman by selling him to Real Madrid for £24 million.
PETER SILLETT | From Southampton | £12k | 1953
Peter Sillett was Chelsea's top-scoring defender with 34 goals until John Terry came along. The Blues signed Sillett from a debt-ridden Southampton, along with his brother John, for a fee of £12,000.
Sillett was part of the team that won Chelsea's first league title in the 1954-55 season and scored the penalty which effectively clinched the title. In total, he made 288 appearances for the club but, surprisingly, only earned three caps for England.
ROY BENTLEY | From Newcastle | £11k | 1948
Roy Bentley remains the joint-fifth top goalscorer in the club's history, level with the immortal Peter Osgood. He served in the Royal Navy during the Second World War before he embarked on a football career.
He arrived at Chelsea in 1948 in a £11,000 deal from Newcastle United. He went on to be the leading scorer for the club for eight successive seasons and scored 21 goals in 41 games as the club earned their first ever top-flight title in 1954-55.
CHARLIE COOKE | From Dundee | £72k | 1966
Charlie Cooke broke Chelsea's club record by signing for £72,000 to join Tommy Docherty's side in 1966. He played in a legendary Chelsea team alongside the likes of Peter Bonetti, Peter Osgood and Alan Hudson.
Cooke helped Chelsea win one of their most famous matches, the 1970 FA Cup final versus Leeds United. He set up Osgood's equaliser in the replay at Old Trafford before the Londoners eventually won the match 2-1 after extra-time.
Chelsea also won the Cup Winners' Cup against Real Madrid the following year with Cooke in their side. He made 410 appearances for the club and he then returned as manager just two years after he left. He is credited with helping to save the club from financial ruin as he got the side promoted from the Second Division once again.
EDDIE MCCREADIE | From East Stirlingshire | £5k | 1962
McCreadie is both a legendary player and manager for Chelsea and he turned down Fulham to join the club in 1962. He helped a young side gain promotion to the First Division and stayed at the club for the next decade as a player.
He scored the winner in the League Cup final of 1965, reportedly dribbling 80 yards up the pitch before firing past Gordon Banks in a 3-2 win.
He also featured in the 1970 FA Cup final win against Leeds United and he played his part in Chelsea's Cup Winners' Cup triumph a year later.