Gawen was a maester of the Citadel who served as Grand Maester during the reigns of Kings Aegon I, Aenys I, and, albeit briefly, Maegor I Targaryen.
Gawen served as Grand Maester for King Aegon I Targaryen, succeeding Grand Maester Lyonce in 12 AC. Gawen and Ser Osmund Strong, Aegon's Hand of the King, were charged with raising walls around King's Landing.
Gawen continued to hold the office of Grand Maester during the reign of Aegon I's heir, King Aenys I Targaryen. When Aenys fell ill at Dragonstone in late 41 AC, Gawen despaired of improving the king's condition.
Following the death of Aenys I, the elderly and grey-headed Gawen protested the coronation of Aenys's half-brother, Maegor I Targaryen, by his mother, Visenya Targaryen. Gawen stated that following the laws of inheritance the crown should pass to Aenys's oldest son, Prince Aegon. Maegor beheaded Gawen for his protests with Blackfyre. After Gawen's death, there were no further protests at Dragonstone. Gawen was the first of three Grand Maesters who were executed during Maegor's reign, the others being Myros and Desmond.