Efforts to implement a constitution for all Silesian estates and thus unite the fragmented country were positive aspects of the 16th century. Sigismund's attempts in the 15th century were only temporarily successful, while Matthias Corvin's reforms achieved more. The king always had representatives in Silesia, for a short time called "Oberlandeshauptleute" (senior governors), otherwise called advocates. Sometimes these advocates were split between Upper and Lower Silesia; these terms appeared for the first time in the 15th century. The "Fürstentage" ("Princely diet"), initially only irregular meetings, became yearly events, although sometimes split between Upper and Lower Silesia. The diets dealt with questions such as tax collection (tax demands by the overlord were a novelty), troop deployment or coinage. A supreme "Princely court" (Czech: "knížecí soud"; German: "Fürstenrecht") was established for the first time in 1498 to settle disputes between the king (then Vladislaus II of Bohemia and Hungary), the princes and barons (free lords) & the estates of 3 duchies: Głogów (Glogau), Opole-Racibórz and Żagań (Sagan).