In 1212 the French king needed an obedient vassal to marry Alix, Duchess of Brittany and turned to his cousin Peter, a younger son of the Count of Dreux.

Brittany became a lay peerage of the France in 1297 and was formally recognised as a duchy (rather than a county) by the French court.

Traditionally, females had been able to succeed as duchesses, but this practice was not consistent with most apanages granted by the French crown, which usually preferred male-only succession.

[2] This prince was imposed in 1212 by the King of France Philippe Auguste as husband to the Alix, Duchess of Brittany.

For a century (from 1213 to 1316), the shields and banners of the Breton princes bore the Dreux chessboard of gold and azure (yellow and blue) with a quarter of ermine.

However, in medieval heraldry it was an element of law that only one person per nation could bear a unique coat of arms.

Jean III could not accept this from his stepmother and since he could not forbid her to bear the arms of Dreux, he decided to change his own.

But, by the 14th century, the fleurs-de-lys having become the central element of French royal heraldry, the chequy had lost its initial prestige.