The year 1415 began in Switzerland with an epoch-making event. In the turbu-
lence which surrounded the imposition of the imperial ban on Duke Frederick IV
of Austria by Emperor Sigismund of Luxemburg as punishment for supporting the
anti-pope John XXIII at the Council of Konstanz in 1415, troops from all the can-
tons invaded the Aargau, with Bern, Zürich, and Luzern to the fore. This Habsburg
possession stretching northwards to the Rhine was destined to remain in Swiss
hands; indeed, traditional Swiss historiography has regarded the occupation of the
Aargau as heralding the death throes of Austrian dynastic lordship in Switzerland.
Moreover, the conquest had wider implications for the exercise and consolidation
of Swiss Confederal sovereignty, since the newly acquired territory was placed
under collective rule in what was termed a ‘common lordship’ (gemeine Herrschaft),
though Bern successfully asserted exclusive authority to the west in the Upper
Aargau.1 The administration of this and subsequent common lordships required
regular consultation between the cantons, thereby underpinning the role of the
Confederal diet (Tagsatzung) as the forum for conflict resolution and foreign policy
debates—in effect the Helvetic parliament—though it never acquired a permanent
bureaucracy, a constitutional code, or a settled meeting-place.2 It has been reck-
oned that the diet devoted almost a third of its business to the administration of
the common lordships before the Reformation.3
The events of 1415 and their aftermath have also been taken as a turning point
in other respects. They suggest that for the northern Swiss cantons further territorial
expansion—by conquest, purchase, or alliance—up to and beyond the Rhine in
areas largely under Austrian Habsburg control informed their thinking, whether in
terms of predetermined intent or as swift reaction to unforeseen opportunities (see
Map 1). The theme of aggressive outreach directed against a Habsburg enemy in
1 See now Christian Hesse, Regula Schmid, and Roland Gerber (eds), Eroberung und Besitznahme.
Die Eroberung des Aargaus 1415 im europäischen Vergleich (Bern, 2017). Still useful is Ernst Bucher,
‘Die bernischen Landvogteien im Aargau’, Argovia, 56 (1944), 1–191. On Habsburg attempts at
revindication see Peter Niederhäuser, ‘damit si bei dem haus Osterreich beleiben—Eidgenössische
Kleinstädte und ihre Beziehungen zum Reich und zu Habsburg’, in Sonja Dünnebeil and Christine
Ottner (eds), Außenpolitisches Handeln im ausgehenden Mittelalter: Aktueure und Ziele (Forschungen
zur Kaiser- und Papstgeschichte des Mittelalters. Beihefte zu J. F. Böhmer Regesta Imperii, 27)
(Vienna/Cologne/Weimar, 2007), 59–75.
2 See Andreas Würgler, Die Tagsatzung der Eidgenossen. Politik, Kommunikation und Symbolik einer
repräsentativen Institution im europäischen Kontext (1470–1798) (Frühneuzeit-Forschungen, 19)
(Epfendorf am Neckar, 2013).
3 Niklaus Bütikofer, ‘Zur Funktion und Arbeitsweise der eidgenössischen Tagsatzung zu Beginn
der Frühen Neuzeit’, Zeitschrift für historische Forschung, 13 (1986), 15–41, here at 26.
1
Setting the Scene