Final answer:
Arthur becomes the true king of Briton mainly through the legendary act of pulling the sword from a stone, symbolizing his divine right to rule or by proving his lineage or worthiness. The story of King Arthur is a central theme in British mythology and involves themes of chivalry and nobility.
Step-by-step explanation:
The question 'How does Arthur become true king of Briton' refers to the legendary tale of King Arthur, which is often explored in English literature and history classes. In the various legends of King Arthur, he is said to have become the king by pulling a sword from a stone, an act that could only be performed by the true king.
This sword is often called Excalibur, and its removal by Arthur is emblematic of his divine right to rule. In other stories, Arthur was the rightful heir to the throne and proved his lineage or worthiness through his noble deeds and leadership in battle.
The legendary King Arthur of the Britons is a Heroic figure intertwined with themes of chivalry, honor, and the noble quest, all central to stories and myths about his reign. Arthur's ascension to the throne often symbolizes the unification and defense of Britain against various threats, making him a key figure in British mythology.