Although history can be unclear.
King of Prussia.com : Community InformationAll agree that the inn was named to honor Frederick the Great, the King of Prussia from 1740 to 1746, but the political reasons behind the name are debated. One theory asserts it was named prior to the Revolution, to honor Frederick’s assistance to the British in the seven Years War with France, which ended in 1763. Others argue it was named to recognize Frederick’s support and admiration for George Washington during the Revolution. A more sales-oriented idea is that it was named to attract the business of Prussian soldiers camped at Valley Forge. But on a spy map of 1777, the inn is referred to as “Berry’s,” the name of the general manager at the time. In 1850 the postal service made common usage official, recognizing the surrounding town’s name as “King of Prussia.”
