Who said "The measure of a ruler is how well he sleeps at night."?

This quote is attributed to Frederick the Great.

The measure of a ruler is how well he sleeps at night. - Frederick the Great

"The measure of a ruler is how well he sleeps at night."

Frederick the Great

Military King Prussian 1712–1786

"I have resolved never to start an unjust war, but never to end a just one except by conquest."

"A prince who loves his people and is loved by them is never in danger of rebellion."

"The more you own, the more it owns you."

"I am the first servant of the state."