In 1018, King Bolesław I the Brave invaded Kievan Rus (see Boleslaw I's intervention in the Kievan succession crisis, 1018), capturing Kiev, and annexing Red Strongholds. In 1340, Red Ruthenia came under Polish control, which intensified defensive Polish settlement and the introduction of Catholicism. After the Union of Lublin 1569, more Polish settlers moved into the eastern borderlands of the vast Polish-Lithuanian Commonwealth.