Edict of Restitution

However, as the Holy Roman Empire descended into the Thirty Years' War, weak emperors had been unable to enforce this provision against Protestant encroachments.

[1] Some Protestant princes interpreted this principle to mean that the Peace of Augsburg allowed secularization of lands held under Catholic church officials who converted to Protestantism.

In Europe at this time, and in particular the German states within the Holy Roman Empire, control over land and its inheritance was frequently contested, as it was the main source of both power and wealth.

The "Edict of Restitution" attempted to retroactively enforce Ferdinand's interpretation of the "Ecclesiastical Reservation" of the Augsburg treaty, effectively undoing changes in control over large areas of land.

This dramatic expansion in the scope and stakes of the Thirty Years' War was very destructive to Germany's lands and people, as mercenary armies marched through neutral states or ravaged them in the course of their foraging expeditions.

Central Germany was ravaged repeatedly, probably losing between 25% and 50% of its pre-war population because the competing armies continually seized food, causing widespread famine and deaths.

Many princes opposed this, but had no immediate means of resisting it, with the Coalition destroyed and Wallenstein keeping an army of 134,000 troops in the field to enforce Imperial authority.