The Church’s victory in the “Investiture Controversy,” throwing off the domination achieved over it by secular powers following the death of Charlemagne, made it the first domain to successfully assert the right to manage its activities in accord with its own principles. But victory was only partial, leaving spiritual and secular powers facing each other across a field of constantly shifting relationships, giving heterodoxy more room to survive than elsewhere. An early example was the contrast between European universities, established as associations of teachers and students formed to assert autonomy from town authorities, and Islamic madrasas subject to direction by their elite patrons. When the corpus of Aristotelian texts became available, first in Arabic and later in Latin, it was first greeted with enthusiasm by readers of both, followed by suspicion because Greek materialism posed threats to religious doctrines. In Muslim lands, this led to a widespread rejection of philosophical inquiry as a path to truth; in Europe, attempts to impose similar restrictions failed, because university faculties resisted the claims of churchly conservatives to limit what could be taught. In this situation, scholastic speculation generated radical ideas about cosmology and physics, foreshadowing the break with traditional cosmology two centuries later.

In the period from 1050–1150 we see law and life ricocheting off each other, and rapid changes in both. Early fifth-century canon law provided a basis for imperial intervention in doubtful papal elections, legitimating Leo IX, who initiated the papal turn. In a number of areas the earliest papal jurisprudence provoked reform. The mismatch between law and life was a long-term result – in an age of urbanization! - of the post-Roman ruralization of Christianity. Ancient canon law was designed for city Christian communities concentrated around the bishop. It was ill-adapted to a world of isolated parish priests who could not be expected to maintain celibacy within marriage. Similarly, election of bishops by the ‘clergy and people’ was less practicable in a large rural diocese than in a concentrated urban community. The papal turn found expression in new legislation, notably about celibacy, which now meant something different from the celibacy required by late Antique papal law. But the new rules proved too simplistic, and further legal evolution followed. ‘Gratian’ expanded by his own commentary the meaning of canons – including papal decretals from late Antiquity – for his own age.