and entrusted to Oleg's hands his son Igor, for he was very young. Oleg moved the capital to Kiev (by murdering the then-rulers and taking the city) and founded the state of Kievan Rus', which was ruled by Rurik's successors (his son Igor and Igor's descendants). The state persisted until the Mongol invasion in 1240. Legacy The Rurik dynasty (or Rurikids) went on to rule Kievan Rus', and ultimately the Tsardom of Russia, until 1598, and numerous noble families in the former lands of Kievan Rus' claim male-line descent from Rurik. The last Rurikid to rule Russia was Tsar Vasily IV (from the House of Shuysky, cadet branch of the House of Rurik), who reigned until 1610. The Romanovs were also related to descendants of Rurik. They were related to Rurik through marriage. The descendants of the princely families allegedly inherited from Rurik are still living. As there are no remains of Rurik, the DNA of Rurik himself cannot be studied. The Y chromosomes of people thought to be the modern descendants of Rurik are often a subset of haplogroup N, traditionally called N1c and now known as N1a. Since then, the same N1c form has been found in other princely families descended from Rurik. These families are called Rurikids. However, not all the supposed descendants of Rurik have it. Alternative theories The name Rurik is a form of the Old Norse name Hrœrekr. Rorik of Dorestad was a member of one of two competing families reported by the Frankish chroniclers as having ruled the nascent Danish kingdom at Hedeby. He may have been a nephew of king Harald Klak. He is mentioned as receiving lands in Friesland from Emperor Louis I. He started to plunder neighbouring lands: he took Dorestad in 850, attacked Hedeby in 857, and looted Bremen in 859, while his own lands were ravaged in his absence. The Emperor was enraged and stripped him of all his possessions in 860. After that, Rorik disappears from western sources for a considerable period of time. In 862, according to the Russian sources, Rurik arrived in the eastern Baltic and built the fortress of Ladoga. Later he moved to Novgorod. Rorik of Dorestad reappeared in Frankish chronicles in 870, when his Friesland demesne was returned to him by Charles the Bald. In 882 Rorik is mentioned as being dead (without a date of death specified). The Russian chronicle places