Complex sentence: The Age of Apocalypse briefly replaced the universe of Earth-616, although it was later retconned as having occurred in the alternate universe of Earth-295, it had ramifications in the main Marvel Comics universe.
Split into simpler sentences: The Age of Apocalypse briefly replaced the universe of Earth-616, although it was later retconned as having occurred in the alternate universe of Earth-295. Still, it had ramifications in the main Marvel Comics universe.