First Time Lord (The War Games)

The Doctor's trial was presided by the First Time Lord, who led the court alongside the Second Time Lord and Third Time Lord. (TV: The War Games) By one account, he was literally known as the First Time Lord of the High Tribunal, (PROSE: Doctor Who and the Doomsday Weapon) although others suggested he was instead a Lord President of the High Court or Council, (PROSE: The Three Doctors, World Game) Inquisitor, (PROSE: Second Session) High Chancellor, (PROSE: Save Yourself) or Councillor. (PROSE: The Legacy of Gallifrey)

By several accounts bolstered by the two's identical appearances, this Time Lord was Goth in the same incarnation that met the Fourth Doctor. (PROSE: The Legacy of Gallifrey, Future Imperfect, War Crimes) However, accounts of the First Time Lord as a figure of ultimate status in Time Lord society dispute this, with sources indicating he regenerated into a new First Time Lord (PROSE: Doctor Who and the Doomsday Weapon) or President in the era of the Third Doctor. (PROSE: The Three Doctors)

Origins
While on Gallifrey, the First Doctor had seen this same incarnation of Goth presiding over CIA hearings. (PROSE: Future Imperfect)

Another source indicated that prior to the trial Goth was a Prydonian Councillor in Pandad IV's High Council. (PROSE: The Legacy of Gallifrey)

In a source with this Time Lord as President, Lady Serena had been studying the records of the most recent presidential election in the Capitol Library, attempting to work out the truth of what actually happened and where it lay between the lines of the official accounts. (PROSE: World Game)

Facing the Second Doctor
The first action of the First Time Lord's Court in cleaning up after the War Games was the trial of the War Lord. The court found him guilty and sentenced him to dematerialisation as if he had never existed.

The First Time Lord then lead the trial of the Second Doctor for violating the non-interference policy. Following a first session in which the Doctor pled his case, the court decided on the punishment of exile to Earth and forced regeneration into his third incarnation. During the second session, the First Time Lord revealed that Jamie McCrimmon and Zoe Heriot would be sent back to their own times with no memories of their travels. He also pronounced the Doctor's sentence, but, after he rejected the choices offered to him for his next incarnation's appearance, the President bluntly told the Doctor that the choice would be made for him before enacting his punishment, forcing the Doctor to change his body at that time. (TV: The War Games)

The court also made several other rulings dealing with the War Games, including one on how to deal with the War Lords experimental subjects such as Ossu. Goth was the only Lord in that ruling to vote for killing the experiments. (PROSE: War Crimes)

There were, however, accounts that the commonly understood version of events was a fabrication, the minutes of the Doctor's trial having been substantially re-edited for the public record. (PROSE: World Game) Alternative accounts existed where the prosecution went more deeply into the Doctor's travels. (PROSE: The Trial of Doctor Who, Second Session)

The true record was eventually released under the provisions of the Gallifreyan Freedom of Information Act. The President of the Court told the Doctor that the theft of a TARDIS was a relatively minor offence that could be pardoned, but told the Doctor that the Court's hands were tied on the second matter. Instead of telling the Doctor he would be exiled, the President instead told him that his prolonged and temporal interference drew attention to the the very existence of the Time Lords and that the safety of their race had lain in silence and secrecy for many years. He went to surmise that offences of this nature were capital crimes before reluctantly sentencing him to death. The charges were commuted to a period of exile after the Doctor struck a deal with Sardon and agreed to work for the CIA. (PROSE: World Game)

To better control him, the Doctor was routinely wiped of his recent memories and put through repetitions of his trial. In one such repetition, the court was presided by a High Chancellor. (PROSE: Save Yourself)

Continued activity
Some further actions of Goth occurred in the context of his role as First Time Lord.

By one account, the three Time Lords who prosecuted the Second Doctor continued to covertly influence the universe using the Station as their base. Goth once met up with Socra and Adelphi to decide to send the Third Doctor to Peladon. (PROSE: Legacy)

On behalf of the Celestial Intervention Agency during the First Omega Crisis, Goth masqueraded as the fictional character Lemuel Gulliver in the Land of Fiction to monitor the Second Doctor. When the Doctor recognized him and feared he would be taken to Gallifrey for trial, Goth told the Doctor that "that time is long in your future and long in our past." (PROSE: Future Imperfect)

Fate
By some accounts, this incarnation continued to operate on Gallifrey as Goth until his final death after allying with. (PROSE: The Legacy of Gallifrey, TV: The Deadly Assassin)

Other accounts indicated that this Time Lord regenerated into a new form, maintaining his high status. The First Time Lord who sent the Third Doctor to Uxarieus remembered having been him. (PROSE: Doctor Who and the Doomsday Weapon) The President during the First Omega Crisis also remembered having been this Time Lord. (PROSE: The Three Doctors)