Lord Valerian of the House of Rassilon was a high ranking Time Lord and the second President to reign during the Last Great Time War, following Livia.
He was posted to Outpost Delta which during the war had became overcrowded. Even though he supported the traditional Presidential candidates, he wanted the Phaidons to settle as it would then have a grounds to have a presidential election. He tried to persuade Trave to get the War Council to allow the settling as he would then give them more power. (AUDIO: Celestial Intervention)
When Livia resigned from the presidency, Valerian was first choice as her replacement. Trave said that he could trace his family back to Rassilon. He was happy to have Romana II as his rival in the election process. He tried to use Romana's imprisonment by the Daleks against her. This proved to be short-lived, however, as he was selected to be the host for the resurrection of Rassilon, which turned out to be fatal. (AUDIO: Desperate Measures)