The thirteenth century marked the great turning-point in medieval political thought: an idea of the state was clearly acquired and located within an overtly political and this-worldly dimension. This development had its roots in the twelfth century and was the product of the assimilation of ideas derived from the study of Aristotle and Roman law in universities. Theocratic, hierocratic and feudal conceptions continued nevertheless to exist in parallel with these new ideas and the result was dialogue, interaction and confrontation. Political thought thus became more complicated and variegated in the late Middle Ages, as it mirrored the development of medieval society. A new world was emerging in which territorial states made the universalist claims of the empire anachronistic, while increasing urbanisation and commercial activity contributed to the decay of feudalism. The preoccupations which had dominated political thought in the high Middle Ages suffered a prolonged sea-change and new concerns joined them.

The political context

Relations between the papacy and secular rulers

The main preoccupation of political thought in the high Middle Ages was clearly the relationship between the church and secular rulers, and in particular that between the papacy and the empire. The history of conflict between the popes and the emperors continued after 1150, and indeed the reign of Frederick I Barbarossa (1152–90) saw a major confrontation with pope Alexander III. Frederick sought to apply in practice the universalist conception of Roman emperorship found in the Corpus Iuris Civilis, the study of which he favoured at Bologna.