The rebellion of Hermenegild and his conversion form one of the most controversial and darkest episodes in the history of Spain. Even at the time, this event was the subject of widely differing interpretations which influenced subsequent versions. Today, there is still no consensus among researchers on the real reasons for the crisis that finally led to civil war between Leovigild and his son. However, from the outset, the issue was polarised between those who saw it as a simple usurpation motivated by ambition for the crown and those who considered the rebellion as a legitimate defence of the true faith. Beyond the controversy, the crisis caused by the prince’s royal anointing was a decisive episode in the historical development of the kingdom of Toledo, preparing the ground for the conversion of Reccared to Catholicism and accelerating the unification of Arians and Catholics, Goths and Romans. This study aims to provide a coherent response to the main questions raised by this important historical episode (the nature of the rebellion, the true motivations and reactions, personal responsibilities, political and religious consequences, etc.), as well as highlighting the importance of Hermenegild’s conversion in relation to the subsequent sacralisation of the Visigothic royal institution.