The name Mieczysław has ancient origins connected to Polish history. It arose from a misreading of the medieval name Mecisław. Although the final etymology of its component is disputed, it is clear that the name does not have a direct connection to the Ukrainian word "меч" (sword). The original meaning of the component "mieczy-" in the name is likely related to the action of "throwing" or "casting." Among Ukrainians, the name Mieczysław is considered rare. It was actively used in Ukraine, particularly in the 15th century. For example, in 1489, there is a recorded mention of the name Nicolaus Mieczysław.During the interwar period, the name Mieczysław became popular in the city of Yaroslav among students of Ukrainian gymnasiums. However, according to Y. Grytsak, Ukrainians were probably indebted to Polish culture for its usage. The name Mieczysław is also recorded in Ukrainian name dictionaries.Some researchers, including L. Makhnovets, believe that the name Mieczysław may be related to the figure of the Galician prince Oleg-Mstislav Yaroslavich from the 12th century. In the 20th century, the name Mieczysław gained popularity in the cities of Lutsk and Khmelnytskyi.