The Battle of Condawn was a conflict in the Clone Wars where Luke Starkiller's father Annikin died by the hands of the treacherous Sith Lords of the galactic capital of Alderaan.
Ben Kenobi's Kiber Crystal was taken by Darth Vader, Ben's apprentice, during the battle and later hidden on Alderaan after he joined the Sith.
Behind the scenes
This battle is mentioned only in the third draft of the original film. It became the subject of a considerable amount of fanon before the release of the Prequel trilogy.