Isidore bishop of Seville was one of the most representative and influential intellectuals of the early Middle Ages. He devoted his life to the idea of transforming the Visigothic Realm (converted to the Catholicism in 589) in a Christian respublica. In realising this ideal, Spanish church needed to persuade the secular (Gothic) elites to join the project. The construction of a common cultural background was therefore a fundamental step and Isidore’s impressive literary production can be understood under this awareness. His most famous work – the Etymologies: a sort of encyclopaedia in 20 books – is the attempt to present all human knowledge in an exposition that was at once coherent and accessible. It became an indispensable reading also for those people who were interested in studying law. Isidore moves well within the tradition of Roman law but he has no compunction from deviating from (and renewing) that. He was not a jurist, nonetheless he gave some original and important contributions to the theory of law (relaunching the ideal of ‘the two laws’ and underlining the necessary ethical foundation of any power) and to the construction of a functional and coherent model of judicial procedure which could be used by both ecclesiastical and secular courts.