The Kingdom of Prussia briefly held land in Estonia.

The statement is false. The Kingdom of Prussia did not hold land in Estonia. Estonia was mostly under Swedish rule until it was ceded to the Russian Empire in the early 18th century. The Kingdom of Prussia, which existed from 1701 to 1918, was primarily focused on the territories within present-day Germany, Poland, and Russia. While Prussia did expand its territories during its existence, Estonia was not among them. Therefore, the statement is not accurate.