The violation of the primogeniture, however, gave grounds for the estates to perceive the upcoming duke Francis II as illegitimate. This forced him into negotiations, which ended on 16 December 1585 with the constitutional act of the "Eternal Union" () of the representatives of Saxe-Lauenburg's nobility (Ritterschaft, i.e. knighthood) and other subjects (Landschaft), mostly from the cities, Lauenburg upon Elbe and Ratzeburg, then altogether constituted as the estates of the duchy (Ritter- und Landschaft), led by the Land Marshall, a hereditary office held by the family von Bülow. Francis II accepted their establishment as a permanent institution with a crucial say in government matters. In return Ritter- und Landschaft accepted Francis II as legitimate and rendered him homage as duke in 1586.