The House of Zasà Âawski (plural Zasà Âawscy) was the name of a PolishâÂÂRuthenian noble family and a cadet branch of the Ostrogski family. The Zasà Âawski family had its power base in Volhynia, Crown of the Kingdom of Poland (today in Ukraine), and traced its origins to a branch of the Rurikids that took its name from Iziaslav. Due to their relation to the Rurikids, the Zasà Âawski family held the title of knyaz (prince).
The Zasà Âawski family was one of the three major families in the PolishâÂÂLithuanian Commonwealth to trace its origins to either Kaributas (they used Korybut coat of arms) or, according to modern historical interpretations, the Ruthenian Rurikids; the other two families were the Ostrogski family and the Wià Âniowiecki family. The Zasà Âawski family was sometimes seen as a junior line of the Ostrogoski family.
After the death in 1620 of the last male heir of the Ostrogoski family, Janusz Ostrogski, many of the Ostrogoski possessions were inherited by the Zasà Âawcy. However, the Zasà Âawski family faced a similar fate when their last male heir, Aleksander Janusz Zasà Âawski, died in 1682. Their huge possessions passed to the Lubomirski family (due to their marriage with Aleksander's sister, Teofilia Ludwika Zasà Âawska) and other families of Polish szlachta. A complicated litigation concerning the Ostrogski inheritance continued until the Russian Empire annexed Poland during the Partitions.