King John is a fictionalized version of one of England's least popular medieval rulers. His claim to the throne is challenged by the French, who wish to install John's nephew Arthur as king of England. John quickly agrees to a costly peace, but his defiance of the pope leads to renewed fighting with France. Neither a hero nor a villain, King John spends much of the play as a passive victim of circumstance. His few assertive acts seem to backfire with remarkable consistency. Alienated from his noblemen, the Church, and the common people, John eventually dies not on the battlefield, but on a sickbed.
Queen Eleanor is one of the real powers behind the throne. Her hatred of Constance, her daughter-in-law, leads to persistent quarreling whenever the two encounter one another. Eleanor is most prominent in Acts 1 and 2, where she influences John's handling of the French crisis. She takes on a lesser role in Act 3 and dies offstage in Act 4.
Constance is the widow of Geoffrey, John's elder brother. She shrewdly encourages the French to adopt the cause of her son Arthur, who has grown up in the French court and has his own claim to the English throne. The Anglo-French war in Acts 1 and 2 thus serves Constance's interests. Later in Act 2, however, peace is concluded between England and France, a development that leaves Constance bitter and desperate. In Act 3 Constance struggles to reckon with her son's lost chance at kingship and, later, his capture by the English. Grief at the latter leads her to act in a fashion other characters perceive as "mad" (i.e., insane). She dies in a "frenzy" in Act 4 without ever being reunited with her son.
A young boy, Arthur is the Duke of Brittany, which he co-rules with his mother, Constance. Before his death King Richard the Lionheart named Arthur his heir and then revoked the nomination in favor of John. Far from ensuring a peaceful succession, this decision created two rival factions, each with its own candidate for the crown. Although John is the current monarch, the French and their armies back Arthur's claim. Shakespeare generally portrays Arthur as a child with little real autonomy or power. He is largely at the mercy of the adults in his life—first his mother, then his uncle John. Less cynical than his older relatives, Arthur craves peace and safety, not the power and prestige of kingship. He rightly discerns his status as a potential royal heir places him in grave danger.
King Philip II
Philip II of France is John's main antagonist in Acts 1 and 2. Although Philip makes no personal claim to the English throne, he hopes to see Arthur crowned king of England. Philip's evident reason for backing Arthur is a desire to recover French territories conquered by England. In Act 2 Philip readily agrees to a peace treaty whereby France will regain Anjou, Maine, and other Continental possessions.
Louis the Dauphin is the impetuous heir to the French throne. To avoid war he marries Lady Blanche of Spain but nevertheless finds himself fighting against her uncle King John. After leading a successful invasion of England in Acts 4 and 5, the Dauphin is ordered by Cardinal Pandulph to cease fighting. He refuses for a time before ultimately reconciling with England.
The Bastard begins the play as "Philip Faulconbridge" and is knighted "Sir Richard Plantagenet" in Act 1. The son of Richard the Lionheart and Lady Faulconbridge, he relinquishes his claims to the Faulconbridge estate to acknowledge his royal lineage. John employs him as a military adviser and commander. The Bastard is perhaps the most clear-eyed and astute character in King John. He sees both war and peace as part of an unprincipled power struggle in which there are no true heroes. For him the motivations of both kings can be summed up as commodity, meaning self-interest or expediency.