Kolo Toure
Despite having been an Ivory Coast international for two years before his arrival at Arsenal, Kolo Toure was still something of an unknown quantity when he joined the Gunners for just £150,000 in 2002.
It proved to be one of Arsenal's biggest bargains of the Premier League era, with Toure establishing himself alongside Sol Campbell at the heart of the defence during the Invincible season of 2003-04.
The centre-back also helped the Gunners to the final of the Champions League in 2006 as part of the defence which kept a tournament-record 10 consecutive clean sheets before being beaten by Barcelona in the final.
Toure eventually left Arsenal to join Manchester City in 2009 having made 326 appearances during his seven-year stay at the club, with 225 of those outings coming in the Premier League.
The Ivorian left the Emirates Stadium having won five trophies, including the Premier League title and two FA Cups.