Conversation so far:
What is the WWF champion for Chris Jericho?
In 2001, Chris Jericho became the first Undisputed WWF Champion having won and unified the WWF and World titles by defeating Stone Cold Steve Austin and The Rock.
What two championships did Chris Jericho have at the same time?
In 2001, Chris Jericho became the first Undisputed WWF Champion having won and unified the WWF and World titles by defeating Stone Cold Steve Austin and The Rock.
Which other title did Chris Jericho win besides having won and unified the WWF and World titles by defeating Ston Cold Steve Austin and The Rock?
Chris Jericho was also the fourth Grand Slam winner under the original format.
In what year did Chris Jericho become Undisputed WWF Champion?
In 2001, Chris Jericho became the first Undisputed WWF Champion.
What was taking place for Chris Jericho in the year 2001?
Chris Jericho became a major force in The Invasion storyline in which WCW and ECW joined forces to overtake the WWF.

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