The siege appears to be a reference to the 30 Years War and the role played by one of Zurich’s citizens. During this complex era of armed conflict over territory and religion, in which the Swiss often served as mercenaries, the Swiss first established their legendary practice of armed neutrality. The Republic of Zürich, where Conrad Werdmüller served as mayor, reacted by building improved city ramparts. Werdmüller also lists his civic responsibilities as an official of the city of Wil. Wil is located 40 km (25 miles) east of Zurich, and is the capital of the Wahlkreis of Wil in the canton of St. Gallen. In 1647, a contract named the Defensionale von Wil, was signed. The declaration was a reaction to the belief that the Swedish armies had advanced as far as Lake Constance in the winter of 1646/47. The Swiss Confederation declared “permanent armed neutrality,” a position that would be re-confirmed by the Congress of Vienna in 1815, after the Napoleonic Wars, and adhered to throughout the nineteenth and twentieth-century conflicts. At the Treaty of Westphalia in 1648, which ended the Thirty Years War, the Swiss Confederacy attained legal independence from the Holy Roman Empire, although it had de facto exercised independence since the Swabian War of 1499. It is tempting to link this image of a besieged city to the patron’s justification of the expenditure of building Zurich’s ramparts. The image, whose source is yet to be identified, most likely was produced after historical prints made by artists such as Matthäus Merian (1593–1650) a Swiss–born engraver who worked in Frankfurt for most of his career. See for example, Merian’s Battle of Frankfurt an der Oder published in 1642.

Cited in:
Record of the Art Museum, 1963, p. 19.
Raguin, & Morgan, 1987, p. 87.