Following the death of his father, in May 1799, he assumed the head of the household, obtaining financial independence. Mouzinho maintained, ever the frugal man, copious registers of his receipts and personal expenses, including them later in his autobiography. He returned to Castelo de Vide where, between 1803 and 1804, he occupied his time with tasks associated with the family estate, especially after the death of his maternal grandmother. At the end of 1804, he left for Lisbon where spent his time at the royal court until 1807, an obligation of his family’s position. He was present in Lisbon at the arrival of French troops, under the command of Junot (in November 1807), during the first French Invasion of Portugal.