First of the Time Lords

By some accounts, Rassilon was known by the epithet "First of the Time Lords". (PROSE: The Legacy of Gallifrey, COMIC: The Forgotten)

By one account, this was because Rassilon experienced the first regeneration on Gallifrey. (PROSE: The Legacy of Gallifrey)

When the Tenth Doctor, who considered himself the last of the Time Lords, saw the Seal of Rassilon, he recalled that Rassilon was the "First of the Time Lords". (COMIC: The Forgotten)