[3][4] Ambrogio Spinola had captured Oldenzaal in 1605 and Groenlo a year later – with this the region was under Spanish occupation and they undertook raids.

[1] Oldenzaal's garrison which had been continuously strengthened since it capture and twenty years later the city had around 800 troops along with cannon under the command of Spanish Governor Guillermo Verdugo.

[5] On July 23 the Dutch and English besieged the town and had a good view of the surrounding environment; as a result, Casimir did not find it necessary to construct a circumvallation line against a possible Spanish relief attempt.

A few companies of English were detached against Broeckhuise castle on the outskirts which posed a threat but it was captured within two days.

Oldenzaal was a strategic place for the republic and the fortress walls despite the protests of the city burghers were demolished.