Poland's first historically documented ruler, Mieszko I, was baptized in 966, adopting Catholicism as the nation's new official religion, to which the bulk of the population converted in the course of the next few centuries.
Poland's first historically documented ruler was baptized in 966. Poland's first historically documented ruler were adopting Catholicism as the nation's new official religion, to which the bulk of the population converted in the course of the next few centuries. Poland's first historically documented ruler was Mieszko I.