Who Were King Arthur’s Siblings by Blood?

King Arthur, the legendary King of Camelot, is one of the most famous figures in British and Celtic mythology. While his knights and adventures are widely celebrated, many people are curious about his family background—especially his siblings. Were Morgan le Fay and Morgause really his sisters? Let’s explore the different traditions and sources to uncover the truth.

Arthur’s Parents: Uther Pendragon and Igraine

Arthur was the son of Uther Pendragon, the High King of Britain, and Igraine, the Duchess of Cornwall. Igraine had been married before meeting Uther, which means Arthur’s family tree is a blend of different bloodlines.

This is the key to understanding who his siblings were: Arthur had half-sisters through his mother, but no universally recognized full siblings.

Arthur’s Half-Sisters (Same Mother, Different Father)

Before marrying Uther, Igraine was the wife of Gorlois, Duke of Cornwall. Together, they had daughters who became Arthur’s maternal half-sisters:

1. Morgan le Fay

• The most famous of Arthur’s sisters.
• Often depicted as a powerful sorceress.
• In some stories, she is Arthur’s ally; in others, she becomes his bitter rival.
• Her name appears in many spellings: Morgana, Morgaine, or Morgan le Fay.

2. Morgause (sometimes called Anna)

• Married King Lot of Orkney.
• Mother of Gawain, Agravain, Gaheris, Gareth, and Mordred (the knight who would later betray Arthur).
• In some darker versions of the legend, Mordred is even described as Arthur’s child with Morgause, adding to the tragic nature of the story.

3. Elaine of Tintagel

• Less well-known than her sisters.
• Some texts describe her as a noblewoman married into another royal family.
• Rarely mentioned in later romances, but she still appears in the early genealogies.

Foster Brother: Sir Kay

Though not related by blood, Arthur grew up with Sir Kay (Cei in Welsh legend), the son of Sir Ector, who raised Arthur.

• Kay is often described as Arthur’s foster-brother.
• Their bond represents Arthur’s humble upbringing before he was revealed as king.
• Important distinction: Kay is not a blood sibling, but is central in Arthur’s early life.

Did Arthur Have Full Siblings?

Most medieval sources, including Geoffrey of Monmouth’s Historia Regum Britanniae, say Arthur was the only child of Uther and Igraine. This means he had no full brothers or sisters, only maternal half-siblings.

Why the Confusion?

The Arthurian legends come from many different sources—Welsh myths, French romances, and later English retellings. Each storyteller added new twists:

• Some merged Morgause and Morgan into one character.
• Others gave Arthur additional half-brothers or even mysterious full siblings.
• Over centuries, the family tree became more legendary than historical.

Final Answer: Who Were King Arthur’s Siblings?

By blood, Arthur’s siblings were:

• Morgan le Fay (half-sister)
• Morgause (half-sister)
• Elaine of Tintagel (half-sister)

He had no full siblings, but he did have a foster-brother in Sir Kay.

In short: Arthur was the only son of Uther and Igraine, but he shared his mother with three famous sisters who each played key roles in the Arthurian legends.