Mieszko I of Poland mentions a gift or dedication of Mieszko's land to the Pope (the act took place almost a hundred years earlier). It is roughly his borders that Poland was returned to in 1945. There is no certain information on Mieszko I's life before he took control over his lands. Only the "Lesser Poland Chronicle" gives the date of his birth as somewhere between the years 920–931 (depending on the version of the manuscript), however, modern researchers don't recognize the Chronicle as a reliable source. Several historians on the basis of their investigations postulated the date of Mieszko I's birth to have
Spytihněv I, Duke of Bohemia Spytihněv I, Duke of Bohemia Spytihněv I (c. 875 – 915), a member of the Přemyslid dynasty, was Duke of Bohemia from 894 or 895 until his death. He was the eldest son of Duke Bořivoj I, the first historically documented Bohemian ruler, and his wife Ludmila. Spytihněv and his younger brother Vratislaus were still minors at the time of their father's death about 889, and the Bohemian lands were placed under the regency of their suzerain, the Great Moravian ruler Svatopluk I. After Svatopluk died in 894, an inheritance conflict arose between his sons Mojmír II and Svatopluk II.