Boxing's purest title — "the man who beat the man". Not a belt handed out by a sanctioning body, but a crown that only passes when the recognised number one is beaten in the ring.
What it means. Anyone can hold a "world title" — there are four major belts per division. The lineal championship is different: it traces an unbroken line back through everyone who beat the previous best man. It's why fans call it the truest measure of who the champion really is.
The heavyweight line, below, runs from the first gloved champion in the 1880s all the way to today. (For current belt-holders in every division, see the Champions page.)