Frederick wrote that Poland had "the worst government in Europe with the exception of Turkey". After a prolonged visit to West Prussia in 1773, Frederick informed Voltaire of his findings and accomplishments: "I have abolished serfdom, reformed the savage laws, opened a canal which joins up all the main rivers; I have rebuilt those villages razed to the ground after the plague in 1709. I have drained the marshes and established a police force where none existed. … t is not reasonable that the country which produced Copernicus should be allowed to moulder in the barbarism that results from tyranny. Those hitherto in power have destroyed the schools, thinking that the uneducated people are easily oppressed. These provinces cannot be compared with any European country—the only parallel would be Canada." However, in a letter to his favorite brother, Prince Henry, Frederick admitted that the Polish provinces were economically profitable: