After he accepted the office of Regent of Germany on 5 July 1848 (see below), John maintained that he could not undertake his responsibilities in Frankfurt until he had fulfilled his responsibilities in Vienna. Therefore, he set out for Frankfurt on 8 July, the same day that the Austrian Ministry led by Baron Franz von Pillersdorf fell. After being appointed Regent in Frankfurt, he returned to Vienna on 17 July, and solemnly opened the Diet on 22 July as the Emperor's representative. Shortly thereafter, the Archduke resigned his official duties and departed for Frankfurt. This caused the Diet to petition for the Emperor's return to Vienna, and he did so on 12 August.