Zurich, when Zwingli went to it, was an imperial city. It had grown up around the Great Minster and the Minster of Our Lady (the Little Minster), and had developed into a trading and manufacturing centre. Its citizens, probably owing to the ecclesiastical origin of the town, had long engaged in quarrels with the clergy, and had generally been successful. They took advantage of the rivalries between the heads of the two Minsters and the Emperor's bailiff to assert their independence, and had passed laws subordinating the ecclesiastical authorities to the secular rule. The taxes were levied on ecclesiastical as well as on secular property; all the convents were under civic control, and liable to State inspection. The popes, anxious to keep on good terms with the Swiss who furnished soldiers for their wars, had expressly permitted in Zurich what they would not have allowed elsewhere.
The town was ruled by a Council or Senate composed of the Masters of the thirteen "gilds" (twelve trades' gilds and one gild representing the patriciate). The Burgomaster, with large powers, presided. A great Council of 212 members was called together on special occasions.
The city of Zurich, with its thoroughly democratic constitution, was a very fitting sphere for a man like Zwingli. He had made a name for himself by this time. He had become a powerful preacher, able to stir and move the people by his eloquence; he was in intimate relations with the more distinguished German Humanists, introduced to them by his friend Heinrich Loriti of Glarus (known as Glareanus). He had already become the centre of an admiring circle of young men of liberal views. His place as people's preacher gave to a man of his popular gifts a commanding position in the most democratic town in Switzerland, where civic and European politics were eagerly discussed. He went there in December 1519.
His work as a Reformer began almost at once. Bernhard Samson or Sanson, a seller of indulgences for Switzerland, came to Zurich to push his trade. Zwingli had already encountered him at Einsiedeln, and, prompted by the Bishop of Constance and his vicar-general, John Faber, both of whom disliked the indulgences, had preached against him. He now persuaded the Council of Zurich to forbid Samson's stay in the town.