I have to point out that Spain, French, England, and Germany were the largest kingdoms in europe during that period, so they may have some conquered territories that they no longer have
But the one that undergo most territorial changes sine the 1600s would be : Germany
In the 1600s Germany used to be divided into several kingdom states. In 1871 Otto Von Bismarck unified Germany under 1 kingdom. Under hitlers' administration in 1940s , Germany conquered several countries in europe under its wing, and after they defeated by the allies, the country was divided into eastern and western front. In the 2000's, the berlin war was destroyed and Germany was unified again
