Supreme Privy Council
Originally, the council included six members — Alexander Menshikov, Fyodor Apraksin, Gavrila Golovkin, Andrey Osterman, Peter Tolstoy, and Dmitry Mikhaylovich Golitsyn. Several months later, Catherine's son-in-law, Karl Friedrich, Duke of Holstein-Gottorp, joined the Council. During Catherine's reign, the Council was dominated by her former lover Prince Menshikov.
In her testament, the Empress authorized the Council to wield power equal to that of her successor Peter, except in the matters of succession. After Peter II assumed the throne, Menshikov persuaded him to marry his daughter. By the time of Menshikov's downfall in September 1727 the Council's constitution had changed drastically: Apraksin died, Tolstoy was exiled, and Duke of Holstein left Russia. Thereupon it was expanded to eight members, of which six represented old boyar families opposing the Westernization reforms of Peter the Great — the Dolgorukovs and the Golitsyns. The other two seats were retained by Osterman and Golovkin.
As the conservative influences prevailed among its members, the Council — although nominally a consultative body — monopolized supreme power and had the imperial capital moved back to Moscow. The collegia (i.e., ministries) and the Senate, instituted by Peter the Great as supreme governing bodies, were not called "governing" any more and were held accountable before the Council rather than the Emperor.
After Peter II's death in 1730, the Council chose a rather improbable successor — Anna Ivanovna, Duchess of Courland, whom they deemed easily amenable to manipulation and too conservative to restore Peter I's reforms. Anna was allowed to ascend the throne only after she had signed the famous conditions, which conferred on the Council the powers of war and peace and of taxation. According to the conditions, Anna couldn't promote officers to ranks higher than colonel and interfere into military affairs. She promised not to marry and not to choose herself a successor. The conditions were modeled on the form of government recently instituted in Great Britain and, if implemented, would have led to Russia's transformation into a constitutional monarchy. In case she violated the conditions, Anna was to be dethroned.
A month after signing the document, on 25 February, Anna, on the advice of her close counsellor, Ernst Johann von Biron, won the sympathies of the Leib Guard and tore up the terms of her accession. Within days, the Council was abolished and many of its members were exiled to Siberia.