Chelsea won the English top flight title in 1954/55 for the first time - their only league triumph before the Premier League era began.
The Blues have had plenty of glory in cup competitions winning the FA Cup eight times in 1970, 1997, 2000, 2007, 2009, 2010, 2012 and 2018, and the League Cup five times, the first time in 1965.
In 2012, Chelsea became the first London club to win the UEFA Champions League. They beat Bayern Munich on penalties in the final following a 1-1 draw at the Allianz Arena, incidentally the home ground of their opponents on the night.
Pochettino was replaced by former Leicester boss Enzo Maresca in June 2024.
Mourinho announced himself in style in a press conference, famously telling the media: "Please, don’t call me arrogant. Because what I am saying is true, I am European champion so I am not one of the bottle. I think I’m a special one." This led to him being nicknamed 'The Special One,' a tag which has stuck with him ever since.
In 2004/05, Chelsea steamrolled to the Premier League title with Mourinho at the helm. They picked up 95 points and conceded only 15 goals, with captain and centre back John Terry being named PFA Players' Player of the Year.
However, UEFA Champions League success eluded the Blues. They lost 1-0 on aggregate to Liverpool in the semi-finals, going down to Luis Garcia's infamous 'Ghost Goal' which seemingly did not cross the goalline.
In 2014, Mourinho added the final pieces to his puzzle, bringing Thibaut Courtois back from his loan and signing Diego Costa, both from Atletico Madrid, alongside the arrival of Cesc Fabregas from Barcelona. Chelsea stormed to the Premier League title once again and also won the League Cup, beating Tottenham 2-0 in the final.
The 2015/16 season got off to a disastrous start and Mourinho was sacked in December with the Blues floundering near the bottom of the table.
In 2009, Carlo Ancelotti was appointed manager. He steered Chelsea to the 2009/10 Premier League title playing an attacking brand of soccer. The Blues scored a record 103 goals en route and doubled up with another FA Cup crown.
In 2010/11, Ancelotti's Chelsea finished second in the Premier League and he was sacked following the completion of the season.
Hiddink took over again following Mourinho's second departure. He steadied the ship somewhat, but Chelsea still finished a miserable 10th in the Premier League.
In 2016, Antonio Conte took the reins and started playing with three defenders in his formation. This proved a masterstroke, as Chelsea won the 2016/17 Premier League title.
The following season was not as successful. Chelsea beat Mourinho's Manchester United in the final of the FA Cup, but a fifth-place finish in the league was not impressive enough for Conte to keep his job. He was replaced by Maurizio Sarri.
Chelsea legend Frank Lampard was named head coach ahead of the 2019/20 season and guided a youthful squad to fourth place in the Premier League in his first season.
The German manager quickly steered Chelsea back on the path to success.
Before the start of the 2021/22 season, Chelsea won the UEFA Super Cup by beating Villarreal 6-5 on penalties following a 1-1 draw.
Substitute goalkeeper Kepa Arrizabalaga was the hero, saving Raul Albiol's spot-kick at Windsor Park in Belfast. Hakim Ziyech had opened the scoring for Chelsea in the 27th minute, with Villarreal's equaliser coming through Gerard Moreno in the second half.
With the off-field turmoil surrounding Abramovich's sale of the club due to the Russian invasion of the Ukraine, Chelsea's season began to go off the rails.
Chelsea moved swiftly to find a replacement, announcing the appointment of Brighton manager Graham Potter as their new head coach on a five-year contract, less than 48 hours later.
The club paid £21.5m in compensation to Brighton in order to release Potter and his backroom staff, a record fee paid by an English club for a manager and second only to the figure stumped up by Bayern Munich in 2021 for Julian Nagelsmann.
But Potter lasted just shy of seven months in the job, following a defeat to Aston Villa that dropped them into the bottom half of the Premier League table and extended the team's poor run of form to just four wins from 19 games in the league.
However, confidence that he was the right man for the job was tested to its limit by the loss to Villa, which yet again saw Chelsea struggle to live up to expectations set by Boehly's mammoth £566million transfer spend.
Despite a willingness to give the 47-year-old the time he needed to get results out of the club's expensively-assembled recruits, it was felt that patience ultimately could no longer be justified and the club acted to give the team the best chance of finishing the 2022/23 season strongly.
At the end of the season, Pochettino left his role by mutual consent after guiding the club to a sixth-placed finish.
His 11-month spell in charge of Chelsea ended with five successive league wins, earning a Europa Conference League place for next season.
Chelsea appointed former Leicester boss Enzo Maresca as their new head coach on a five-year contract in June 2024 - the third permanent managerial appointment since Todd Boehly’s Clearlake Capital consortium bought the club two years ago.
Under the Italian’s leadership, the Foxes secured an immediate Premier League return a year after being relegated.
Roman Abramovich stepped in at a time of financial trouble for Chelsea, buying the club from Ken Bates for £140million in 2003.
Abramovich oversaw the greatest period of success in Chelsea's history, delivering five of their six top-flight titles and two UEFA Champions League crowns.
The early years of the Abramovich era, in particular, were characterised by regular chopping and changing of managers. However, that has slowed down somewhat since the second coming of Jose Mourinho.
The Russian's ownership tenure in West London has been typified by a stream of high-profile signings, often for big money, alongside an extremely successful model of sending a high number of their contracted players out on loan to clubs around the world.
Abramovich was seen as an engaged, hands-on owner at the Blues, being present at almost all Chelsea matches and offering his support throughout his time at the club.
The club confirmed that a group led by Todd Boehly and Clearlake Capital had purchased the club in a £4.25billion deal in May.
The Group also own baseball's Los Angeles Dodgers, the basketball teams LA Lakers and the Los Angeles Sparks.
Tottenham Hotspur are the club which Chelsea supporters generally love to hate most. Spurs were once the more successful of the two and snapped up legendary striker Jimmy Greaves in 1961 following his spell at Chelsea and a short stint at AC Milan.
However, Chelsea's success under Abramovich is the subject of resentment among Tottenham supporters. Chelsea's 2012 Champions League win denied Tottenham a place in the following season's edition of the competition and they signed winger Willian a year later when he had been destined for a move to Spurs.
Arsenal are also bitter rivals of Chelsea. The rivalry between former Arsenal manager Arsene Wenger and Mourinho exacerbated the animosity between the clubs.
Chelsea also have a fierce rivalry with Leeds United, which intensified in a hot-tempered 1970 FA Cup final, which saw the Blues win the replay.
Their more recent rivalry with Liverpool has strengthened as a result of numerous UEFA Champions League battles and competing against each other in title races.
As of May 2023, Chelsea are the eighth most valuable football club in the world, with an estimated value of $3.1bn.
Chelsea boss Enzo Maresca has told Cole Palmer to concentrate on enjoying his football as he attempts to replicate last season's heroics.
Bournemouth are eager to complete a loan deal for Chelsea goalkeeper Kepa Arrizabalaga.
Chelsea boss Enzo Maresca insists his squad is well organised and calm about the season, despite a number of recent transfer deals in both directions.
Chelsea have secured the services of Atletico Madrid's Joao Felix on a seven-year contract, 15 months after playing for the club on loan.
Chelsea midfielder Conor Gallagher has parted ways with the Premier League club to sign for LaLiga outfit Atletico Madrid.
Chelsea have agreed a deal with Atletico Madrid to sign Joao Felix which could see midfielder Conor Gallagher move to the Spanish club.
Raheem Sterling’s days at Chelsea appear to be numbered – the question is, will the England man move on deadline day?
