The End of the Rus State Founded by Vikings
To this day, Vladimir the Great is one of the greatest saints of the Eastern Orthodox faith. In an attempt to avert future fratricidal strife such as the one he had experienced, Vladimir set up a succession hierarchy known as the Rota System. In it, power passed not from father to son, but to the oldest member of the ruling dynasty. Thus, power passed from brother to brother, from oldest to youngest, thence to nephews in the next generation by age.
Vladimir’s succession system proved problematic. Members of the Rurik dynasty hurried up their turn or secured succession for their sons by murdering each other. It went bad soon as Vladimir died in 1015, when his eldest son murdered three of his siblings to kick off his reign. He in turn was defeated and killed by one of his younger brothers in 1019. That kind of instability eventually fragmented Kievan Rus into de facto independent statelets, that owed only nominal fealty to Kiev. Kievan Rus went into decline, until it was wiped out by the Mongols in the thirteenth century.