Question: the city ,in the Vecht valley of the Salland region is at the heart of what Provence, was a commercial and defensive confederation of merchant guilds and their market towns ?
Sentence (from "Ommen"): Ommen (] ) is a municipality and a Hanseatic city in the Vecht valley of the Salland region, which is at the heart of the province of Overijssel in the eastern Netherlands.
Relevant evidence: Yes