Final answer:
In the legend of King Arthur, Arthur is forced to sentence Guinevere to death due to her betrayal with Sir Lancelot; however, she is rescued by Lancelot before the execution.
Step-by-step explanation:
The question refers to the legendary story of King Arthur, specifically what actions King Arthur was compelled to take against Guinevere following her betrayal. In the Arthurian legends, Guinevere is involved with Sir Lancelot, which constitutes her betrayal against Arthur. According to the traditional stories, Arthur, bound by the laws and customs of the time, was forced to sentence Guinevere to death by burning at the stake. However, she is rescued by Lancelot before the execution could be carried out. The legends vary, but the story of Guinevere's betrayal and Arthur's resulting actions are pivotal in the tales of the Arthurian legend, underscoring themes of loyalty, honor, and the tragic consequences of infidelity.