The evolution of Polish involvement in crusading was in step with the process of state formation in Poland and the individual fortunes of the Piasts … - Darius von Guttner-Sporzynski

In theory, there were no legal limits to the monarch’s power over his realm. In practice, however, the king was bound by the laws and customs of the land, and exercising his authority depended on the agreement of France’s elite: the nobility and the clergy.

The Piast realm serves as an example of how the character of the crusade changed in response to shifting military, social, economic, and political circumstances. The taking of the cross by the Piasts and their knighthood was a way of responding equally to both domestic and European strategic developments.

Within a decade of the First Crusade, the anonymous author of the Gesta justified the holy war against the Pomeranians.