The last princess of Llyr
Background and beginnings
"Caer Colur itself has long awaited its Princess. It calls to her, and so it ever shall, while one stone stands upon the other."
Eilonwy, as revealed in the first book of the Chronicles, was a princess of the ancient royal house of Llyr. The House of Llyr had been founded by Llyr Half-Speech, the Sea King. Its members – or their forebears – were also known as the Sea People. The family had its seat at Caer Colur, a castle on a peninsula that was once part of the Isle of Mona, but that later broke off to form its own offshore island. The family had a strong tradition of magic which ran mainly in the female line. Although the women of Llyr had once included 'Sword-Maidens'
who fought in battle beside their men, by Eilonwy's time they had become primarily focused on wielding power through magic. 'The boys are war leaders, and the girls are enchantresses,'
was how Eilonwy described her family. Eilonwy herself sometimes looked back to the older tradition, demanding the right to bear a sword like her ancestors.
The Llyr enchantresses recognised a matrilineal line of succession. Eilonwy introduced herself to Taran as 'Eilonwy, daughter of Angharad, daughter of Regat, daughter of – oh, it's such a bother going through all that.'
Caer Colur and its store of magical implements were passed down from mother to daughter. 'For generations,'
as Gwydion explained, 'the daughters of the House of Llyr were among the most skilful enchantresses in Prydain, using their powers with wisdom and kindliness.'
The position of the family was, however, jeopardised by Eilonwy's mother, Angharad. Princess Angharad fell in love with Geraint, a man far below her in social status, and eloped with him when her mother Regat disapproved of their marriage. Since Angharad had left Caer Colur, its guardianship fell vacant; the castle decayed and its treasures were left abandoned and unguarded. Furthermore, Angharad herself was vulnerable outside the protection of the castle. The sorceress Achren, formerly queen of Prydain and longing to regain her crown, saw Angharad as an opportunity to gain control over the power of the House of Llyr.
Achren pursued Angharad and finally stole her infant daughter, Eilonwy. Searching across Prydain to regain her daughter, Angharad died soon afterwards, weakened by her ordeal. Eilonwy was left as the last heiress of Llyr. She grew to adolescence in Achren's palace, Spiral Castle, believing that she had been placed with Achren as a ward in order to learn magic. In reality, Achren knew that Eilonwy, when she came of age, would also be able to access the spells of Caer Colur and come into her mystical inheritance as its princess. She kept Eilonwy from babyhood in order to use the girl as a tool when that time came.