Mstislav III Glebovich

Mstislav III Glebovich was an Olgovichi prince. He was probably prince of Rylsk and of Chernigov. During his reign, the Tatars invaded and pillaged the towns of the Principality of Chernigov.
He was the son of Prince Gleb Svyatoslavich of Chernigov and Anastasia Ryurikovna, a daughter of Grand Prince Ryurik Rostislavich of Kiev. His father died between 1215 and 1220.
By 1225, Mstislav had already been second in seniority among the Olgovichi, and therefore during the absence of his cousin, Mikhail Vsevolodovich, he commanded them. On April 6, 1231, he attended a snem in Kiev, but the reasons for convoking the council are not given. It appears that his domain probably lay west of the Snov and Desna rivers.