 The State Department charged Adams with developing commercial relations with Prussia and Sweden, but President Adams also asked his son to write him frequently about affairs in Europe.In 1799, Adams negotiated a new trade agreement between the United States and Prussia, though he was never able to complete an agreement with Sweden.He frequently wrote to family members in the United States, and in 1801 his letters about the Prussian region of Silesia were published in a book titled "Letters on Silesia".