Question: What castle was built at a strategic point?
Sentence: Feudal levies could only be raised for a fixed length of time before they returned home, forcing an end to a campaign; mercenary forces, often called Brabançons after the Duchy of Brabant but actually recruited from across northern Europe, could operate all year long and provide a commander with more strategic options to pursue a campaign, but cost much more than equivalent feudal forces.
Answer in sentence: no