[3] In 1811 Brandsen joined the army of the Italian Kingdom who fought alongside Napoleon In the Germany campaign he was injured in three separate battles and gained the rank of captain.

Brandsen met at that time Bernardino Rivadavia (who would later become the President of Argentina in 1826) who convinced him to join the fight to liberate the Americas from the Spanish Empire.

When San Martín became Protector of Peru, Brandsen was named leader of the regiment of Hussars of the Peruvian Legion of the Guard, with the rank of lieutenant colonel.

After a brief stay in Santiago he returned to the Río de la Plata where the government made him the leader of the 1st Cavalry Regiment with the rank of lieutenant colonel.

The attack failed, but the battle was won because other colonels such as Tomás de Iriarte, Miguel Estanislao Soler and José María Paz, amended the errors of Alvear.

Brandsen was posthumously promoted to colonel; his remains rest in the Cementerio de la Recoleta, in Buenos Aires, in front of the mausoleum of General Alvear.