At sixteen she married a widowed duke. Another woman's image was painted over to make room for hers. The prayer book prepared for her had belonged to his first wife.

On 30 October 1442, Isabella of Scotland married Francis I, Duke of Brittany, at the Château d'Auray. She was the daughter of James I and Joan Beaufort, a Scottish princess becoming a Breton duchess while her younger brother wore their father's crown. The book that accompanied her new position had already passed through the hands of a mother and daughter. Now it would be altered for her.

Isabella's parents had themselves married far from Scotland. Her father had been a prisoner in England before his release and marriage to Joan, an Englishwoman of the Beaufort family. They travelled north together in 1424 and were crowned at Scone. James returned determined to recover authority from nobles who had grown accustomed to his absence. He arrested rivals, confiscated estates and made enemies powerful enough to reach him in his own lodging.

In 1437, assassins killed him at the Dominican friary in Perth. Joan was badly injured in the attack but survived. Their son James was six when he inherited the throne, and the struggle to control the child king followed. Five years before Isabella's wedding, her family had lost its father and Scotland had acquired another royal minority. A crown had offered very little protection inside those walls.

Her elder sister Margaret had already married Louis, the heir to the French throne. Isabella's marriage carried another daughter of the Scottish house across the sea, this time into a ducal household where the previous wife's belongings remained. Francis had married Yolande of Anjou in 1431. She died in 1440, before he became duke. He inherited Brittany in August 1442. When he married Isabella that October, she became a duchess on her wedding day.

Among the things Francis's first marriage had left behind was an elaborate Book of Hours, a collection of prayers for personal devotion. It had originally been made for Yolande's mother, Yolande of Aragon. Its parchment pages were filled with pictures of Christ, the Virgin and the saints. This was a book in which devotion, money and family had been worked into the same pages.

It was adapted for the new bride.

On one page a woman knelt before the Virgin and Child. Artists painted Isabella's face and heraldic dress over the earlier figure and added Saint Catherine beside her. The woman remained at prayer, but her identity had changed. Her red, ermine-lined clothing now belonged to a Scottish princess married into Brittany. In the border, her own arms were added, the Scottish lion set beside the ermine of her husband's duchy. Marriage had given her a second identity without removing the first.

The alterations were made in stages. At first the new figure retained the earlier woman's headdress. That too was eventually covered, and a ducal coronet painted in its place. Even the little woman on the parchment had to be brought up to date with the marriage. Rank required its visible signs, in a prayer book as readily as at court.

Isabella and Francis had two daughters, Margaret and Marie. The young woman whose image had been fitted into an older book became a mother herself. The volume remained with her through the marriage and into the years after Francis's death in 1450, when the question of where she belonged became a matter for more than heraldry.

Her brother James II wanted her back in Scotland.

She refused to leave Brittany. At an inquiry at Rennes in 1453, Isabella explained that she wished to remain in the country where she had received so much affection and honour. She also complained that her brother had never paid her dowry, the money promised with her marriage. Affection mattered, but so did the means to stay.

The bride had been sent abroad as a king's daughter. The widow answered her brother as a woman with a home of her own. She remained in Brittany.

The prayer book would leave her possession by a different route. It passed to her daughter Margaret, and another prayer and image were added. Margaret appeared kneeling before the Virgin and Child at a desk draped with Breton arms, wearing a tall golden headdress and veil. Isabella's figure remained elsewhere in the volume. The book prepared for a second wife had passed from mother to daughter, and this time there was room for both of them.