Population increased in the mid-17th century because there was more religious tolerance after the Thirty Years' War.
Explanation:
In 1650, the Thirty Years' War had just ended. This war was fought when princes in what is modern-day Germany rebelled against the Catholic Holy Roman Emperor for the freedom to worship as Protestants. When the war ended, there was a declaration of religious tolerance. The idea of a Catholic empire, ruled by one leader and guided by the pope, was over. It was the beginning of modern Europe.
