Figo. Sol Campbell. Clarence Seedorf. Johan Cruyff. What have these four players got in common?
Yep, that's right, they're transfer traitors. these are they players who showed no respect for football's history and traditions by moving from one side straight over to their rivals.
These men and a handful of others have completed some of the most controversial transfers in football history.
Remember when Figo went from Barcelona to Real Madrid? He received the full treatment from the Catalan faithful, and found a pigs' head had been hurled at his feet whilst he took a corner.
And what about when Campbell crossed the north London divide, breaking Tottenham hearts and making Arsenal's day? Even now, some 12 years later, he's still referred to as "Judas" by Spurs fans who can't stand the sight of him.
So with the 2013 summer transfer window well underway and the potential for some more heroes to become villains (ahem, Wayne Rooney) Now's your chance to peek behind the most contenious transfers ever and test your knowledge on football's most controversial moves.