Later on he attempted to influence the Prussian Northern Union in the direction of the national policy, and he took part in the sessions of the Erfurt parliament; but, soon realizing the hopelessness of any good results from the vacillating policy of Prussia, he retired from the contest, and, as a major in the service of the SchleswigHolstein government, took part in the Danish War of 1850.
Throughout the revolutionary years he supported his brother's policy, became a member of the Erfurt parliament, and, after the collapse of the national movement, returned to the service of the duchy of Nassau.
Such were the discouraging conditions which weighed him down at the time of the interview with the tsar at Erfurt (September 27th - October 12th, 1808).
Apart from this advantage, placed in his hands by the imprudence of Stein, Napoleon was heavily handicapped at the Erfurt interview.
These facts, and not, as has often been assumed, the treachery of Talleyrand, decided Alexander to assume at Erfurt an attitude of jealous reserve.