Prince of Smolensk
In 1125 Rostislav's father, Saint Mstislav the Great, granted him Smolensk as his inheritance. He governed the principality for more than four decades, expanding it with new cities and villages and adorning it with churches and monasteries. Among the towns associated with his rule are Rostislavl, Mstislavl, Krichev, Propoisk, and Vasiliev. Through this work he became the founder of the Smolensk princely dynasty.
In 1136 Rostislav established an independent diocese of Smolensk, with Bishop Manuel as its first leader, issuing an edict that guaranteed ecclesiastical support; in 1150 he ceded Cathedral Hill to the diocese. He rebuilt the Dormition cathedral originally constructed by his grandfather Vladimir Monomakh, which was consecrated on 15 August 1150. His other construction projects included the Smolensk Kremlin and the Savior cathedral at the Smyadynsk monastery of Saints Boris and Gleb.