On May 11, 1559, a riot erupted in Perth, Scotland, which resulted in an open revolt against the authority of the Regent, Mary of Guise, and her 'foreign' religion. On that day, the Scottish Reformation slipped out of its covert phase and began to gather momentum as a revolution. The enthusiastic response by the townspeople of Perth to John Knox's preaching is widely documented. The question of why this happened in Perth remains unanswered. This account of Perth in the 16th century addresses the question of 'why Perth?' and reveals some answers to what lay behind the iconoclastic riot of 1559. A tradition of radicalism amongst certain burgesses had proved to be eminently successful over the decades preceding 1559. Political activism had resulted in some very successful manipulations of the system of town government and the extension of these processes to religion was a natural progression. This pattern of reform was unique amongst Scottish towns but was to be found in certain continent