The Eleven's Time Ring (The Side of the Angels)

After one of his previous incarnations suggested to him to make use of a Time Ring because the Time Vortex was too badly damaged and unstable due to Padrac and the Doom Coalitions' plan to save Gallifrey from potential futures which would leave the Time Lords and their homeworld destroyed which would have easily have destroyed a TARDIS, the Eleven travelled to New York to chase after the Eighth Doctor, Liv Chenka and Helen Sinclair.

While the Eleven was on Earth, he stumbled upon a group of Time Lord rebels led by Cardinal Ollistra who had entered into an agreement with Weeping Angels who were already on Earth to power up Gallifreyan buildings so then they could regroup in 500 years to take the fight to Padrac.

The Eleven's presence on Earth foiled that plan, and he killed some of the Time Lords while others escaped when the Weeping Angels got out of control. The Doctor successfully convinced the Eleven's previous incarnations that Padrac didn't care about him and was using him and his skills for the Doom Coalition's own ends, and it caused a lot of upset and mental stress, which the Eight took advantage of and triggered the Time Ring to take the Eleven back to Gallifrey. (AUDIO: The Side of the Angels)

The Time Ring brought the Eleven back to Gallifrey, but it landed him outside the Capitol instead of through the channel Padrac had arranged. When the Time Lords caught the Eleven, the Doctor made use of the Time Ring to get into the Capitol to stop Padrac's plan. The Doctor lied to Liv when he said the Time Ring could not take more than one person. (AUDIO: Stop the Clock)