Sir Thomas is one of the main characters in the series World Without End. He is a knight who has turned on Queen Isabella after learning of her plot to kill King Edward II and sought sanctuary in the Kingsbridge Priery, becoming a monk in the process. In actuality he is King Edward II, thought dead but in fact alive, on the run, and in disguise. He is played by Ben Chaplin.
Sir Thomas first appears in the first episode as a knight on horseback fleeing pursing crossbowmen. He is injured when one crossbow bolt strikes him in the arm while another slays his horse. Fleeing into the nearby woods, he is able to kill his pursuers in a fight, before then collapsing of his injuries and being taken to the Kingsbridge Priery by the brothers Merthin and Ralph, who had been in the woods at the time. His injury is treated by the healer Mattie Wise but later becomes infected. Before Mattie can arrive, the Priery healer Brother Joseph amputates the arm, and Thomas is saved only by the timely arrival and quick thinking of Mattie Wise.
After getting sanctuary at the Priery, Sir Thomas expresses his desire to become a monk, his reason for this being that he was once a knight in the service of Queen Isabella who deserted after learning that she had conspired to have her husband Edward II killed. As a monk in the priery Sir Thomas is guranteed total protection from her wrath. He subsequently attempts to adjust to his new life in the priery, even attempting to better things in Kingsbridge somewhat.
When the black plague breaks out, Thomas alongside Caris and Merthin tries to save as many lives as possible. Tragically, one monk who he was close with, Brother Matthias, succumbs to the plague after being infected by Godwyn. Afterwards he reveals to Caris how he had fled from Queen Isabella and that he is why the queen hates Kingsbridge and goes out of her way to inflict suffering on the city. When he learns that Caris and Merthin plan to leave Kingsbridge because they feel there is no future for them, Thomas produces a document with King Edward II's royal seal that frees Kingsbridge of the corrupt priery's control. He then reveals that he is in fact King Edward II, who had not perished in his prison cell but rather killed his would-be-assassin, took his name as his own, and escaped to Kingsbridge. Unfortunately, once his wife and son learn of this they plan to kill him to maintain Edward III's rule, also intending to destroy Kingsbridge and slaughter it's inhabitants. Rallying the citizens, Thomas/Edward urges them to fight, even to the death. Confronting his son, he manages to best him in a sword-fight but spares his life. He tells Edward III that he can become a better ruler than he ever was, and that if his son spares Kingsbridge Edward II will surrender both his crown and his life. Edward III gives his father his word and then reluctantly kills his father. Fortunately, Edward III maintains his promise, ensuring that Edward II died saving the town that took him in.