The estates within the boundaries of the unoccupied city of "Bremen" weren't restituted by order of the city council. The council argued, that the city had long been Protestant, but the "restitution commission" argued that the city was de jure a part of the Prince-Archbishopric, so Protestantism had illegitimately alienated estates from the "Roman Catholic Church". The city council answered under these circumstances it would rather separate from the "Holy Roman Empire" and join the quasi-independent "Republic of the Seven Netherlands" (Its independence was finally confirmed by the Treaty of Westphalia in 1648). The city was neither to be conquered nor to be successfully beleaguered due to its new fortifications and its access to the North Sea via the Weser river.