▁histor ians ▁also ▁argue ▁this ▁was ▁one ▁of ▁the ▁main ▁reasons ▁that ▁John ▁later ▁became ▁fer vent ly ▁religious , ▁giving ▁him ▁name ▁the ▁P ious ▁( Port ug uese : ▁o ▁P ied oso ). ▁ ▁Initial ▁reign ▁On ▁ 1 9 ▁December ▁ 1 5 2 1 , ▁John ▁was ▁crown ed ▁king ▁in ▁the ▁Church ▁of ▁São ▁Dom ing os ▁in ▁Lis bon , ▁beginning ▁a ▁thirty - six - year ▁reign ▁character ized ▁by ▁extensive ▁activity ▁in ▁internal ▁and ▁over se as ▁politics , ▁especially ▁in ▁relations ▁with ▁other ▁major ▁European ▁states . ▁John ▁III ▁continued ▁the ▁absol ut ist ▁politics ▁of ▁his ▁prede cess ors . ▁He ▁called ▁the ▁Portuguese ▁Cort es ▁only ▁three ▁times ▁and ▁at ▁great ▁intervals : ▁ 1 5 2 5 ▁in ▁Tor res ▁Nov as , ▁ 1 5 3 5 ▁in ▁É v ora ▁and ▁ 1 5 4 4 ▁in ▁Al me ir im . ▁During ▁the ▁early ▁part ▁of ▁his ▁reign , ▁he ▁also ▁tried ▁to ▁rest ruct ure ▁administrative ▁and ▁jud icial ▁life ▁in ▁his ▁real m . ▁ ▁The ▁marriage ▁of ▁John ' s ▁sister ▁Isabel la ▁of ▁Portugal ▁to ▁Holy ▁Roman ▁Emperor ▁Charles ▁V , ▁enabled ▁the ▁Portuguese ▁king ▁to ▁for ge ▁a ▁stronger ▁al liance ▁with ▁Spain ▁and ▁the ▁Holy ▁Roman ▁Empire . ▁To ▁strength en ▁his ▁t ies ▁with ▁Austria , ▁he ▁married ▁his ▁mat ernal ▁first ▁cousin ▁Catherine ▁of ▁Austria , ▁younger ▁sister ▁of ▁Charles ▁V ▁and ▁his ▁erst while ▁f ian c ée