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The Régiment Royal was a French Armyregiment that had been enlarged by renaming and uniting older regiments. At the time, the régiment de l'Altesse and the régiment Royal became one. The regiment Royal was first started 1656 by the Duke d'Arpajon.
References
Nous étions le Nouveau Monde, Jean-Claude Germain, Hurtibise, p145 2009