Originally Posted by BattlingNelson
Lineage and undisputed are two different things.
If you believe that lineage is reestablished when a fight between the no.1 and no.2 (sometimes 3) then Wlad became linear champ when beating Chagaev.
If you need to be undisputed to claim lineage then you'll not have any linear champs today.
Going by your standard then who did Tyson beat to become lineal champ?
The exact lineage is here