How did the Union of Utrecht organize cooperation among the rebelling provinces?

The Union of Utrecht, established on January 23, 1579, organized cooperation among the rebelling provinces by creating a "closer union" intended to function as a single entity while maintaining provincial autonomy.1

Key aspects of this cooperation included:

• Military and Political Integration: The provinces united "for all time as if they were a single province," forming a perpetual military league to resist Spanish rule.1
• Sovereignty and Decision-Making: While each province retained sovereignty over its internal affairs, they acted as a unified body regarding foreign policy. Decisions concerning war, peace, and federal taxation required unanimous consent.1
• Leadership: The agreement confirmed the effective political leadership of the provincial stadtholders, who served as the governors of the provinces.1
• Religious Shift: The union moved away from the broader religious tolerance established by the Pacification of Ghent, trending toward a Calvinist monopoly on public religious practice in key provinces like Holland and Zeeland.1

This framework effectively laid the foundation for the Dutch Republic, distinct from the southern provinces that reconciled with Spain.1