Duke Władysław Odonic ordered that his son be given a comprehensive education; as attested in the Wielkopolska Chronicle, young Przemysł was able to read Latin psalms with ease.

[3] Przemysł first appears in official documents signed by his father from 1232 onward, and after Władysław Odonic's death on 5 June 1239 he began his own rule, during the time of Fragmentation of Poland (1138 - ca.

[6] Despite his success, Przemysł sought to end his disputes with the Silesian Piasts and in 1244 he married Bolesław II's sister Elizabeth,[7] at the monastery in Trzebnica.

Contrary to his plans, this marriage did not calm the situation on the Silesian-Greater Poland border, but it did allow Przemysł to recover Kalisz from Duke Władysław of Opole.

[10] In 1247 Przemysł I was forced by the local knights to give his brother Bolesław the district of Kalisz as a separated Duchy, but in foreign policy he retained full authority over Greater Poland.

A year later, the ruler of Greater Poland crushed the opposition by imprisoning its leaders, the Castellan of Poznań Thomas of Nałęczów and his sons.

[15] During the first half of the 13th century, Przemysł I promoted a more peaceful policy, working closely with his brother-in-law Konrad I of Głogów and giving his sister Euphemia in marriage to Duke Władysław of Opole.

In 1254 he organized an armed expedition against Henry III the White, destroying part of the Bishopric of Wrocław goods (i.e. Oleśnica), for which Przemysł I was excommunicated, and the penalty was only removed after the Greater Poland Duke repaired the damages in the Church states.

The next campaign against Henry III was launched in September of the same year, but this time the joint expedition of Przemysł I, his brother Bolesław and Konrad I of Głogów avoided damages of Church goods.

However, this strategy ultimately back-fired politically as the Ascanians used the marriage to claim rights over the western region of Greater Poland as their "New March".

[19] The establishment of friendly contacts with his relatives proved useful one year later, when Duke Mestwin II of Pomerania captured the district of Nakło.