Alix was about twenty-one when she died, and Brittany passed to her little son. She had inherited it at roughly the age he was then. The man who had governed it through her went on governing it through him.

Alix of Thouars, Duchess of Brittany, died on the date generally given as 21 October 1221. Her son John was three or four years old. She had been younger still when the duchy became hers, after an older brother disappeared and an older sister was kept where she could not claim it.

Their mother was Constance, Duchess of Brittany in her own right. Her marriage to Geoffrey, a son of Henry II of England, had produced Eleanor and Arthur. By the time Alix was born, Constance had married again, to Guy of Thouars. Alix belonged to the same Breton family as her older half-brother and half-sister, but she did not share their English royal father. That difference would matter.

Constance died in 1201, while Alix was very young. Arthur survived his mother, but his inheritance drew him into a struggle with his uncle John, King of England. John captured him in 1202. In 1203, Arthur disappeared in his uncle's custody. He never returned to Brittany.

Eleanor was older than Arthur and had a claim of her own. She was also John's prisoner. Recognising her would have given the Bretons a duchess the English king kept under guard, and given the king a ready excuse to govern Brittany in her name. Her birth gave her a claim. Her captivity put that claim within her uncle's reach. The Breton barons recognised Alix instead, a little girl whose father was available to govern for her.

The duchy was hers. Its government was another matter.

Guy exercised authority for his daughter, but the French king, Philip Augustus, was already intervening. In 1206 he took the government into his own hands. Alix's childhood passed within arrangements made by her father and a king, both acting in a duchy to which her mother had supplied the hereditary right. Being the heiress ensured that she mattered. It did not mean the decisions would wait until she was old enough to make them.

One of those decisions was her marriage. In 1209 she was betrothed to Henri of Penthièvre, another child, from a powerful Breton family. The arrangement offered a Breton husband for the Breton heiress. But a little boy could not provide the military leadership Philip wanted against the English king.

Philip chose again.

His choice was Pierre de Dreux, a grown man, a soldier and a kinsman of the French royal house. Pierre could supply what the first arrangement lacked: an adult commander bound to Philip. He did homage to the king for Brittany, and in 1213 or early 1214 he married Alix. She was about thirteen. Her inheritance brought him authority over a duchy, and Philip gained a member of his own family at its head. Guy had governed for his daughter. Pierre now governed for his wife.

Her name did not vanish when he arrived. Through her mother's line Alix was also heir to Richmond in Yorkshire, an English honour that had belonged to the dukes of Brittany for generations. In 1218 the English government recognised Pierre and Alix together as earl and countess of Richmond, and charters concerning those lands were issued in her name. The same English government was still holding her sister.

They had three children. John was born around 1217, Yolande in 1218 and a second Arthur in 1220. The first Arthur had disappeared when Alix was a toddler. Her younger son bore his name.

Across the Channel, Eleanor remained in custody. John's death in 1216 had not brought her release: his successor, Henry III, kept her confined too. By the time Alix had a husband and children, her older half-sister was still being held by the English crown. The two women had inherited claims from the same mother. One had been married into the French king's family. The other could not leave English custody.

Then Alix died, leaving her little son to succeed her. What killed her is not known. Pierre had governed for his wife, and now he governed for his son, as Guy had once governed for his daughter. John inherited Brittany in 1221 and took its government into his own hands in 1237, when he was about twenty. His mother had not lived much longer than that.