On September 18, 1810, he participated of the open "Cabildo" (city hall) that resulted in the establishment of the Government Junta of the Kingdom of Chile under the presidency of his father, also known as the "First Junta", an action which is generally seen as the first step of the Chilean independence process. From the beginning he was a member of the "royalist" party, the most conservative group that was against any reform at all and for the maintenance of the "status quo".