The Procurator (Russian: прокурор, prokuror) was an office initially established in 1722 by Peter the Great, the first Emperor of the Russian Empire, as part of the ecclesiastical reforms to bring the Russian Orthodox Church more directly under his control.
The Russian word also has the meaning of prosecutor.
The Chief Procurator (also Over-Procurator; обер-прокурор, ober-prokuror) was the official title of the Crown official who oversaw the validity of the acts of the Most Holy Synod (he wasn't a member of the Most Holy Synod but effectively he was the most important lay in the administration of the Russian Orthodox Church, not to be confused with the Primus or "Prime member", the legal chairman of the Most Holy Synod, always a Metropolitan or an Archbishop), and a member of the Tsar's cabinet. Konstantin Pobedonostsev, a former tutor both of Alexander III and of Nicholas II, was one of the most powerful men to hold the post, from 1880 to 1905.
The General Procurator (Procurator General) and the Chief Procurator were major supervisory positions in the Russian Governing Senate, which functioned from 1711 to 1917, with their meaning changing over time. Eventually Chief Procurator became the title of the head of a department of the Senate.