The origins of Château Lamothe-Bergeron lie with the seigneurie of Lamothe, the heart of which was the Château La Motte de Cussac, all of which belonged to the Captale de Buch. Captale (a word derived from the Latin capitalis, meaning chief) was an archaic feudal title similar to seigneur, but which was used in relation to only a few communes. Buch, which is situated on the Atlantic coast overlooking the bay of Arcachon, was one commune with a captale, who happened to own some land around the settlements of Cussac-Fort-Médoc and Lamarque.
At the end of the 15th century the title and lands were in the hands of Nicolas de Lauste; his daughter, Marie de Lauste, Dame de Lamothe, married François Martel, who thus took possession of the seigneurie. This couple had a daughter, also named Marie, and her marriage to Pierre-François de Bergeron (born 1685) in 1720 gives us the origin of the name Lamothe-Bergeron, although in truth this name would only be applied more than a century later. Remarkably, even at this early stage, viticulture was already established here.