Count Dooku was a Jedi Master who fell to the dark side of the Force and became the powerful Sith Lord Darth Tyranus. Dooku was the Jedi who trained Qui-Gon Jinn and the only Jedi besides Yoda, Sora Bulq and Qui-Gon who could defeat Mace Windu in sparring. He was a very wealthy man which was vital for the funding of the Clone Wars and after nearly seventy years of service in the Jedi Order he fell under the influence of Darth Sidious, turning him to the dark side. He replaced Darth Maul as Sidious' apprentice.