Berengar's kin became the first Gallo-speaking lords holding residence within Brittany (Rennes and Penthièvre, rather than the Loire Valley-predominant Nantes or Vannes), as a consequence of the Breton nobility being more or less broken under the Norman invasions of the 880s and as a reward for holding his ground against their attacks.
Jean Marie was born in Paris at the Hôtel de Toulouse, Parisian townhouse of the fabulously wealthy Duke of Penthièvre.
At the death of his older brother Louis Marie de Bourbon, the Prince of Lamballe became the heir to the Penthièvre fortune, much of which had been extorted by Louis XIV from his childless cousin la Grande Mademoiselle, and bestowed upon Louis XIV's legitimised elder son, Louis Auguste de Bourbon, duc du Maine.
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On November 25 of that year, in a long religious procession, Penthièvre transferred the nine caskets containing the remains of his parents, the comte and the comtesse de Toulouse, his wife, Maria Teresa d'Este, and six of their seven children, from the small medieval village church of Rambouillet, to the chapel of the Collégiale Saint-Étienne in Dreux.