- "Henceforth, you shall be known as Darth… Vader."
- ―Darth Sidious, upon making Anakin Skywalker his new apprentice
Darth was a title given to the Dark Lords of the Sith Order, which preceded a moniker different from the birth name. The Sith names of Sheev Palpatine, Dooku and Anakin Skywalker were Darth Sidious, Darth Tyranus and Darth Vader, respectively.
The title was already in use about one millennium before the Clone Wars, when Darth Bane created the Rule of Two. In at least two known cases, that of Dooku and Anakin Skywalker, the Darth title and the accompanying moniker were bestowed onto the Sith apprentice by the master.
The Jedi Master Obi-Wan Kenobi once used "Darth" as a form of address when talking to Darth Vader. It was traditional that only the current Sith Master and his or her apprentice were allowed to use the Darth title. Imperial officers typically addressed Vader as "Lord Vader".