Izyaslav II was the son of Grand Prince Mstislav I
. He came to the throne
of Kiev in 1146
after the death of his cousin Vsevolod II
, and dethroned Vsevolod's brother Igor II
who had only been on the throne for a few months. This brought the descendants of Vladimir II
Monomakh back to power (but not the still-living previously crowned Grand Prince Vyacheslav
, also of Monomakh's family).
Izyaslav was dethroned in 1149 by his uncle (Vyacheslav's younger brother) Yuri I, but in 1151 defeated Yuri and ruled jointly with Vyacheslav until 1154, in an attempt to sound like he had a better claim than Yuri. On Izyaslav's death his brother Rostislav became Grand Prince.
The Kievan Chronicle credits Izyaslav with a useful new way to build ships: "Izyaslav built boats in an ingenious way: the oarsmen were invisible, only the oars could be seen, and the men were not, since the boat was decked. And the soldiers stood on the deck in armor and shot arrows. And there were two helmsmen, one in the bow and one in the stern; and they could steer the boat where they wanted without turning it." Polnoye Sobraniye Russkoy Letopisi, II, str. 59 1151.