 Owing to political feuds with José Miguel Carrera and his brothers, Juan Mackenna was dismissed from the post and taken prisoner.He was a firm ally of Bernardo O'Higgins, who appointed him as one of the key officers to fight the Spanish army of General Antonio Pareja.Mackenna's major military honour was attained in 1814 at the Battle of Membrillar, in which the general assured a temporary collapse of the royal forces.