Abstract
The author deals with the question of what terms were used in the Bohemia in the Middle Ages for military actions. The analysis of the sources showed that the regular military actions taken by the Czech rulers (invasions to neighboring countries and the provision of borders or conquered territories) took place in the spring and early summer of 11-12.
Before the beginning of the harvest, the army returned to Bohemia. At the main harvest, military actions were taken only in cases forced by serious circumstances.
On the contrary, Imperial military actions were regularly launched on summer Marian holidays, mostly in the middle of August, less frequently on 8 September. Here is a hypothesis that the Czech "time of struggle" could be coordinated with the Empire.
While in the spring and early summer, the Czechs were