The defeat of Mohammad Ali Shah in returning to throne for Russia meant that the position of the authoritarians in Iran had weakened and it was no longer possible to return to that government before the Constitutional Revolution. Shortly afterwards, the Russian army stopped advancing and retreated to Tabriz. The Russians tried to maintain their influence in the Qajar bureaucracy. Many princes and politicians took bribes to support Russia's goals in Iran. On the other hand, this worried the Ottoman Empire, which now sought more influence in Iran because it sought refuge with the constitutionalists during the Constitutional Revolution. The conflict between the Russian Empire and the Ottoman Empire over Iran led to the invasion of Iran in 1915 and the beginning of the Persian campaign.