When was the first formally constituted Duma introduced in Russia?

The "Duma" was a Russian assembly with advisory or legislative functions. The term comes from the Russian verb (dumat) meaning "to think" or "to consider". The first formally constituted duma was the State Duma (1906) introduced into the Russian Empire by Tsar Nicholas II after the revolt of people against him in 1905, demanding for the elected assembly.

Under the pressure of the Russian Revolution of 1905, Sergei Witte (prime minister in Imperial Russia) issued a manifesto about the convocation of the Duma, initially thought to be an advisory organ. In the subsequent October Manifesto, Nicholas II pledged to introduce basic civil liberties, provide for broad participation in the State Duma, and endow the Duma with legislative and oversight powers. However,

Nicholas II was determined to retain his autocratic power. Just before the creation of the Duma in May 1906, the Tsar issued the Fundamental Laws. It stated in part that the Tsar's ministers could not be appointed by, and were not responsible to, the Duma, thus denying responsible government at the executive level.

The Tsar had the power to dismiss it and announce new elections whenever he wished. At this first meeting of the Duma, members proposed that political prisoners should be released, trade unions given rights and land reform be introduced. The Tsar rejected these suggestions and dissolved the assembly in July,1906.The imperial State Duma was elected four times: in 1906, twice in 1907, and in 1912.