Frisians had in the 12th century settled Stedingen, an area north of Bremen in the delta of the Weser river in north-western Germany.

Becoming known as Stedingers, they had turned the swamps into polders.

To attract settlers, the settlers had been given many rights and low taxes.

Stedingen had developed into a rich farmer republic in the early 13th century.The archbishop of Bremen and the count of Oldenburg had tried to curtail the rights of the farmers, which had led to a revolt in 1204.

Archbishop Gerhard II of Bremen had excommunicated the farmers in 1228.

He convinces the Pope to declare a 'crusade' against the Stedingers in 1232.

An army of crusaders is initially repelled by the Stedingers in 1233.

The archbishop manages to defeat the Stedingers in the battle of Altenesch in 1234 with a large army of crusaders.

This a rare crusade in the history of the Roman Catholic church, because the Stedingers are neither heathens nor heretics.