The year 241 before the Battle of Yavin (BBY) was a period of time during the declining days of the Galactic Republic. The period was one of transition for the Order of the Sith Lords. Having lived for thousands of years after discovering the secrets of immortality, during which time he fell to the dark side of the Force, former Jedi Grandmaster Damien Nightblade joined the Sith as the apprentice of the Dark Lady Darth Erilis, taking on the name Darth Plagueis. Shortly thereafter, Plagueis became the Dark Lord of the Sith.