The name was extremely popular among Polish royalty, with several leaders shaping the nation's history:
: A prince of the Jagiellon dynasty who was known for his exceptional piety, charity, and refusal of royal luxuries. He is the patron saint of Poland and Lithuania. Fictional: Kasimir Velikov kasimir
The most prominent "Kasimir" in modern history was a Russian avant-garde painter and art theorist. He is celebrated as the founder of , an art movement focused on basic geometric forms, such as circles, squares, and lines, painted in a limited range of colors. The name was extremely popular among Polish royalty,
: Known for reuniting Poland after a period of internal collapse and pagan uprisings, earning him the title "the Restorer". such as circles