Kaunas was a frontier castle prior to Lithuania and Poland’s war with the Teutonic Order in 1409–1411. Vytautas rebuilt the castle of Kaunas while preparing for this war. In 1409, its construction was completed. During this year, Vytautas often visited Kaunas and almost all of his visits were associated with a rebellion in Samogitia (Žemaitija). It can be argued that Kaunas was an important base for Vytautas as he prepared for war with the Order. According to John Dlugosz, Vytautas brought the regiment of Kaunas together with other Lithuanian regiments in the battle of Grunwald (Žalgiris). The Kaunas regiment consisted of members of the nobility within the territorial division of the Kaunas district, but not of inhabitants of the city of Kaunas. Hypothetically, it can be assumed that the regiment consisted of 300 soldiers and was led by Sungaila, the elder of Kaunas. The regiment’s flag was red with the Columns of Gediminas embroidered on it. The Kaunas regiment certainly participated in the battle of Grunwald, which took place on 15 July 1410, and contributed to the victory.

The elections of burgomaster in Kaunas on February 22, 1787 were complicated and caused serious arguments. Even though a Lutheran was elected as the burgomaster, as it was foreseen that year, the elections divided the city community and municipality officers into two groups, which were not based on religious grounds. This was probably the first occasion of this kind, which showed a possible change in values when religion as the main unifying force was replaced by other considerations, most probably disagreements about city governance and management of income and costs.