Rubuta ci gaba don wannan sakin layi - Lokacin da yaƙe-yaƙe a Afirka suka ƙare, Afonso V ya sami sabbin filayen yaƙi a makwabciyar Castile. A ranar 11 ga Disamba, 1474, Sarki Henry na huɗu na Castile ya mutu ba tare da magājin namiji ba, ya bar 'ya ɗaya, Joanna. Duk da haka, an yi shakkar mahaifinta; an yi jita-jita cewa matarsa, Sarauniya Joan ta Portugal ( 'yar'uwar Afonso) tana da dangantaka da wani mai daraja mai suna Beltrán de La Cueva. Mutuwar Henry ta jawo yaƙin neman sarauta
tare da bangare daya na goyon bayan Joanna da kuma goyon bayan Isabella, 'yar'uwar Henry. An shawo kan Afonso V ya shiga tsakani a madadin Joanna, 'yar'uwarsa. Ya yi alkawarin aure da ita, ya ayyana kansa Sarkin Castile kuma ya jagoranci sojoji zuwa masarautar. Domin suna da dangantaka ta kusa ta jini, dole ne a jira izinin papa kafin a yi aure bisa doka.