When Maximilian I wrote his will in 1641, Maria Anna claimed in this for the eventual reign of her son, a co-signature law in national matters. However, the Office of the Administrator in Bavaria and Saxony claimed that according to the Golden Bull women were excluded from government. She consulted an expertise commission without her husband's knowledge and secured a favorable ruling concerning her rights added in Maximilian I's will. Thus, after Maximilian I's death (27 September 1651) his brother Albert VI, Duke of Bavaria legally became the regent for Ferdinand Maria and was confirmed in that position in both Imperial and Electoral courts. Maria Anna assumed full responsibility for the Department of Justice and other country administrative tasks, however, which virtually left the Dowager Electress ruler of Bavaria. In addition to Albert VI and the Dowager Electress, the "Hofkammerpräsident" Mändl belonged to the administration that continued to work with the young Elector when he attained his majority in 1654.