ABSTRACT
Evidence suggests that heresy in Lombardy proliferated during the twelfth and thirteenth centuries, a period of upheaval in the structure and form of politics and society, especially in its capital city. From 1117 Milan operated as a commune, securing independent jurisdiction at the Peace of Constance (1183). From the middle of the thirteenth century the della Torre family dominated Milanese communal office, and by the 1270s the Visconti family had ascended, the start of a lasting signoria. Milan was also embroiled in contemporary struggles between Papacy and empire. Its location on the main trade routes from Venice and the East ensured a strong economy, making Milan attractive to migrants, and by the end of the thirteenth century its population had swollen to an unprecedented level – possibly 175,000. 1
