Conversation so far:
What is the WWF Champion?
CANNOTANSWER.
What WWF was undisputed?
to become the first wrestler to hold both championships at the same time, which made him the first-ever Undisputed WWF Champion.
what 2 championships did he have at the same time?
WWF Championship.
Which other one?
WCW Championship.
In what year did it happen?
CANNOTANSWER.
What was taking place in the year 2001?
Jericho became a major force in The Invasion storyline.

Question: Why was he considered a major force?
Self-contained rewrite: Why was Chris Jericho considered a major force