There has been more than one Diet of Worms. The most famous one is the Diet in 1521. This was the first Diet which attempted to deal with the problem of Martin Luther and Lutheranism. In this aspect it was highly unsuccessful.
Charles V, Holy Roman Emperor of the time, in conjunction with the Pope tried to get the Princes to condemn Luther. However Elector Frederick of Saxony persuaded Charles that Luther should be allowed to present his ideas first. Despite Luther’s clever arguments he was found guilty and the Papal bull was enforced. This decree of condemnation for Luther was called the Edict of Worms.
Luther was guaranteed safe conduct to and from the Diet. On his return journey Elector Frederick kidnapped Luther and spirited him away to a stronghold within Saxony.
Luther was able to stay there until it was safe for him to return to Wittenberg, the city of his studies 1522.