You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
East_Prussia

Context:
The Administrator of Prussia, the grandmaster of the Teutonic Order Maximilian III, son of emperor Maximilian II died in 1618. When Maximilian died, Albert's line died out, and the Duchy of Prussia passed to the Electors of Brandenburg, forming Brandenburg-Prussia. Taking advantage of the Swedish invasion of Poland in 1655, and instead of fulfilling his vassal's duties towards the Polish Kingdom, by joining forces with the Swedes and subsequent treaties of Wehlau, Labiau, and Oliva, Elector and Duke Frederick William succeeded in revoking king of Poland's sovereignty over the Duchy of Prussia in 1660. The absolutist elector also subdued the noble estates of Prussia.

Question:
Who revoked the King of Poland's sovereignty over Prussia in 1660?

Frederick William