Armand de Gontaut, Baron of Biron (French pronunciation: [aʁmɑ̃ də ɡɔ̃to], 1524 – 26 July 1592) was a soldier, diplomat and Marshal of France. Beginning his service during the Italian Wars, Biron served in Italy under Marshal Brissac and Guise in 1557 before rising to command his own cavalry regiment. Returning to France with the Peace of Cateau-Cambrésis he took up his duties in Guyenne, where he observed the deteriorating religious situation that was soon to devolve into the French Wars of Religion. He fought at the Battle of Dreux in the first civil war. In the peace that followed he attempted to enforce the terms on the rebellious governorship of Provence.
Having fought for the crown during the decisive victory at Battle of Moncontour in 1569, he was elevated to the post of grandmaster of artillery. In this role he was tasked with reducing the town of Saint-Jean-d'Angély which proved resistant to his efforts. As the war dragged on he found himself increasingly involved in diplomatic efforts, meeting with Jeanne d'Albret repeatedly to talk terms. With peace declared in August 1570 he continued his negotiations with Albret in the hopes of setting up a marriage between her son Navarre and Margaret of Valois. In the wake of the Massacre of Saint Bartholomew he was tasked with reducing the well defended city of La Rochelle, commanding the artillery batteries he made limited progress over the following months, before Anjou oversaw peace negotiations so that he might depart for the Poland-Lithuanian Commonwealth.