What happened in the Diet of Worms of 1521? (and what is it?)

https://www.thoughtco.com/the-diet-of-worms- [login to see]
On April 18, 1521, at the Diet of Worms, Martin Luther answered questions about books he had written. From the article:

"The Diet of Worms 1521
Luther made his first appearance on April 17th 1521. Having been asked to accept that the books he’d been accused of writing were his (which he did so), he was asked to reject their conclusions. He asked for time to think, and the next day conceded only that his writing might have used wrong words, saying that the subject and the conclusions were genuine and he stuck by them. Luther now discussed the situation with Frederick, and with a man working for the Emperor, but no one could make him recant over even one of the 41 statements the Papacy condemned him for.
Luther left on April 26th, with the Diet still afraid condemning Luther would cause a rebellion. However, Charles signed an edict against Luther when he had gathered some support from those who remained, declared Luther and his supporters illegal, and ordered the writings burned. But Charles had calculated wrongly. The leaders of the empire who hadn’t been at the Diet, or who had already left, argued the edict didn’t have their support."