The Belosselsky-Belozersky princely and Rurikid family is an aristocratic Russian family that descends in a direct male line from the Earliest Kievan Rus rulers and later of the medieval sovereigns of the Principality of Beloozero.
The family of Belosselsky-Belozersky claims the descendance directly from the first Russian Princes, from the "Kiev Rus" period and specifically from Prince Rurik (of Swedish roots), who created their seat in Kiev around the years 870–890. The family traces its patrimonic, father-to-son roots throughout the ruling houses of Russia until the mid 16th century, to Yuri Dolgoruky (founder of Moscow) and his grandsons who were grand-dukes/princes of Kiev as well as of Vladimir-Suzdal principality. After the ascendance of Ivan Kalita ("Moneybags") and the Romanov dynasty, the family were rulers of the Belozersk (White Lake) principality, north of Moscow. Gleb Vassilkovich was the first Belozersky prince to rule there. While on one of the required annual visits to Sarai, the headquarters of the Golden Horde (near today's Astrakhan), to renew his patent (yarlik) received from the reigning Khan and ruler of the Golden Horde Sartak Khan, allowing thus Gleb to rule and tax his lands for another year. On this visit, Gleb married Feodora, Sartak's daughter (Feodora Sartakovna) (also granddaughter of the Mongol ruler Batu Khan and great-great-granddaughter of Genghis Khan. Gleb Vassilkovich thus consolidated the power of the dominant Tatar-Mongol rulers and the Belozersky clan. The offspring of Gleb and Feodora Sartakovna, the current Belosselsky-Belozersky family, are thus descendants of Genghis Khan as well as of the founder of Russia, Prince Rurik. Subsequently, the family, after having lost the majority of its men in the historical "watershed" battle for Russia's independence, the battle of Kulikovo in 1380, against the Tatar-Mongol dominance, the few remaining Belozersky princes slowly lost the control of the lands in the Belo Ozero/Belozersk principality area (White Lake). The family was relegated thereafter to a more minor ruling role over the lands of "Belo Selo" south of Belozersk (Thus the name "Belosselsky" - of White Village) when the Moscow principality led by Moscow Romanovs were slowly taking control over all the former semi-independent principalities of Russia. After a period of lesser prominence, but still providing military and political leaders, it became a major factor in support to Peter the Great's reforms, in building the Russian navy and providing diplomats and military leaders. In early 1800 Alexander Mikhailovich Belosselsky-Belozersky, due to his significant contributions to Russia in diplomacy, science and culture, was granted the right to bear the double princely name of Belosselsky-Belozersky from Emperor Paul I, in recognition of the Belosselsky branch being the single remaining such branch of the princes having ruled Belo Ozero and being of the Belozersky dynasty.