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.
See the List of The Top Best 15 Signings
15. 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.
14. 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.
13. 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.
11. 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.
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.
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.
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.
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.
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.
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.
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.
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.
Didier Drogba is the king of Stamford Bridge due his remarkable achievements as part of the greatest group in the club's history.
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.
14. 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.
13. ROY BENTLEY | From Newcastle | £11k | 1948Roy 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.
