By the terms of his Regency, Archduke John was forbidden to take part in the drafting of the Frankfurt Constitution, which was adopted on 28 March 1849 after lengthy negotiations led by Gagern. He pronounced against the strong position of Prussia and was determined to resign, but he was once more turned over by appeals from National Assembly President Eduard von Simson. When, in April 1849, King Frederick William IV of Prussia disappointed Gagern's hopes and openly rejected the Constitution, Archduke John remained passive and reminded his Prime Minister of the terms of his service as Regent, forbidding his interference in the process. Prime Minister Gagern handed in his resignation on 10 May.