Alfonso had shown himself a skilled and determined soldier, helping his father in the suppression of the Conspiracy of the Barons (1485) and in the defence of the Kingdom's territory against the Papal claims.
Alfonso telah menunjukkan dirinya seorang prajurit yang terampil dan gigih, membantu ayahnya dalam penindasan Konspirasi Baron (1485) dan dalam membela wilayah Kerajaan melawan gugatan Kepausan.