Calzaghe very briefly. When he beat lacy he had the WBO and IBF, and then he still held both for the one fight with kessler to lift the WBA and WBC titles. So, he held all 4 before being stipped of the IBF.
Roy Jones held at one time the WBC WBA IBF NBA WBF IBO IBA This content is protected Not sure if the Ring Belt was around when he unified if so, add that one to the war chest as well.
Everybody who is good should drop the IBO belt as in the future there is the possibility of a 5th credible belt- God help us...
:rofl Its a funny thing our sport, you can hold/unify all the titles, which is a hell of an achievement but in reality its just overkill and detrimental, as has been mentioned already lol