The events of "X2: X-Men United" take place.
Nightcrawler attacks the White House demanding Mutant Freedom. Magneto escapes from prison. William Stryker’s forces attack the X-Mansion. X-Men join forces with Magneto and Mystique against Stryker. After their attack on Stryker’s base at Alkali Lake, Jean Grey is killed.
Note: Nightcrawler is theorized to be the son of Azazel and Mystique. Because of Azazel's death, he was more than likely born sometime in between 1963 and 1973.