Bestuzheff-Riumin, a Russian family of English origin, originally named Best. On their settlement in Russia they took the name of Ruma, which was changed by Peter the Great to Riumin. - Petee Mikhailovitch was Russian minister at Hamburg, and received the rank of count from Peter. - Mikhail, his son, born in 1686, was Russian ambassador at Stockholm, grand marshal under the empress Elizabeth, and from 1756 to 1760 ambassador at Paris. His wife, sister of Count Golovkin, entered into a conspiracy with Lapushin against Elizabeth, on the discovery of which she was knouted, had her tongue cut out, and was exiled to Siberia. - Alexei, count, brother of Mikhail, born in Moscow in 1693, died in April, 1766. He was educated at Berlin and Hanover, where he was presented to George I. of England and entered his service. In 1718 he returned to Russia, and was sent by Peter the Great as ambassador to Copenhagen. Under Anna he was minister to Hamburg and Copenhagen, and afterward a cabinet minister. Under Elizabeth he was made grand chancellor of the empire.

In 1745 he concluded a treaty of alliance with England, and in 1743 a treaty with Sweden by which the royal succession in that country was regulated according to the wishes of Russia. In 1746 he formed a treaty of alliance with Austria against France and Prussia, and in 1748 sent an army into Germany under the command of Repnin. Soon after he occasioned the ruin of Lestocq, his former patron. Through his influence the Russian troops supported Austria against Frederick the Great in the seven years' war; but their commander, Apraxin, suddenly retired to Russia, and this occasioned the fall of Bestu-zheff, who was suspected of having recalled him in the interest of a political intrigue. (See Apraxin.) He was degraded, but Catharine II. in 1762 restored him to liberty and to his previous social position, creating him a field marshal. He is regarded as the inventor of a preparation known in medicine under the name of tinctura tonica Bestusewi.