European Union law fair dealing through their business. In 1517, the Protestant Reformation triggered a hundred years of crisis and instability. Martin Luther nailed a list of demands to the church door of Wittenberg, King Henry VIII declared a unilateral split from Rome with the Act of Supremacy 1534, and conflicts flared across the Holy Roman Empire until the Peace of Augsburg 1555 guaranteed each principality the right to its chosen religion ("cuius regio, eius religio"). This unstable settlement unravelled in the Thirty Years' War (1618–1648), killing around a quarter of the population in central Europe. The Treaty of Westphalia 1648, which brought
Peace of Münster for approval; it was ratified by the Spanish and Dutch delegations on 15 May, with the States General narrowly approving the Treaty on 5 June 1648. The Peace of Münster together with the Treaty of Münster between the Holy Roman Emperor, France and their allies and the Treaty of Osnabrück involving the Holy Roman Empire, Sweden and their allies were collectively known as the Peace of Westphalia. While European conflict continued, this marks a significant point in the transition to sovereignty based on states rather than individuals e.g. the Hapsburgs. Sovereignty has been defined by historian Harry Hinsley as "the