Przemysł I (4 June 1221 – 4 June 1257), a member of the Piast dynasty, was Duke of Greater Poland from 1239 until his death, from 1241 with his brother Bolesław the Pious as co-ruler. He was able to re-acquire large parts of Greater Poland, ruling as Duke of Poznań and Gniezno from 1247 and, upon several inheritance conflicts with his brother, as Duke of Poznań and Kalisz from 1249, sole Duke of Greater Poland from 1250, and Duke of Poznań from 1253 until his death. The numeral primus ("The First") was given to him in the almost contemporary Wielkopolska Chronicle.