Imperial crown
In 1840 he was reinstated in his professorship, and in 1841 was chosen rector of the university. The revolutionary outbreak of 1848 rekindled in the venerable patriot his old hopes and energies, and he took seat as one of the deputies to the National Assembly at Frankfurt. He participated in the deputation that offered the Imperial crown to Frederick William IV, and was indignant at the king's refusal to accept it, so he retired from public life.