Chelsea have been one of the most successful English clubs since the turn of the century.Since winning their second English league title, first in the Premier League era, in 2004-05 under Jose Mourinho, Chelsea have triumphed four more times in the competition besides winning a bevy of domestic titles. The Blues have also tasted success in the Champions League (once) and in the Europa League (twice) during the last two decades.5 players you didn't know played for ChelseaConsidering the recent history of Chelsea and their growing stature in domestic competitions and Europe, a number of fine players have turned up for the club over the years.However, as is the case at times, some players failed to make a mark at the club or had largely forgettable stints but went on to enjoy greater success elsewhere. On that note, let us have a look at five such players in no particular.#5 DecoDecoDeco is one of the most illustrious names in Portuguese football, but the attacking midfielder only provided fleeting glimpses of his talent during his two-season stint at Chelsea in the late 2000s.After successful stints at Porto and Barcelona, where he made a name as a world-class player in midfield, Deco had a largely underwhelming stint with Chelsea despite helping the club to a league and cup double in 2009-10.A combination of injuries, loss of form and inconsistency meant that Deco never became a darling of Stamford Bridge. Chelsea fans often wonder what might have been had the Portuguese international arrived at the club a few years earlier than he eventually did."That's what Deco can do!"A vintage volley from @Deco20oficial for the Blues against Bolton. 👌 pic.twitter.com/H0E45OFmEt— Chelsea FC (@ChelseaFC) December 23, 2017Deco moved to Brazilian club Fluminense in 2010 and called time on his career three years later.#4 Didier DeschampsDidier DeschampsArguably one of the finest defensive midfielders of all time, France's 1998 World Cup-winning captain Didier Deschamps is not remembered by many for his short stint at Chelsea in 1999-2000.After successful spells with Marseille and Juventus, where Deschamps made his name as a defensive midfielder of repute, the Frenchman arrived at Stamford Bridge when he was apparently past his prime and struggled to make the kind of impact he would have liked to.Deschamps, the current France manager, made a total of 47 appearances for the Blues... #CFC pic.twitter.com/Pg1WLlnmwA— Chelsea FC (@ChelseaFC) October 15, 2014Nevertheless, Didier Deschamps won the FA Cup during his lone season at Chelsea and also scored in the Champions League against Hertha Berlin. The Frenchman left Stamford Bridge in 2000 and played a season at Valencia before hanging up his boots at the age of 32.