Principality of Mstislavl
Мстиславское княжество
Coordinates : 54°01′10″N 31°43′19″E / 54.01944, 31.72194
Map of the principality of Mstislav
Capital Mstislavl
Government Principality
 -  1180-1223 Mstislav III Romanovich of Kiev (c1167-1223)
Historical era Middle ages
 -  Separation from the Principality of Smolensk 1180
 -  Formation of the Province of Mstislavl 1566

The Principalityh of Mstislavl was an appanage Russian principality with its capital in Mstislavl, separated from the Principality of Smolensk in the 12th century. Its first prince, in 1180, was Mstislav Romanovich. The territory of the Principalithy of Mstislavl included the territories of the present Mstislavl, Cherykaw and Chavusy rayons (districts} with the cities of Radoml and Ryasno .

After the death of the Prince of Smolensk Davyd Rostislavich, Mstislav Romanovich's uncle, in 1197, the latter was recognized as Prince of Smolensk and again annexed the principality of Mstislav to Smolensk, retaining it however as a separate appanage .

At the end of the 13th century, the principality of Mstislavl appeared on the Russian-Lithuanian border, and in 1359 it was annexed by Algirdas and annexed to the Grand Duchy of Lithuania . Later, the principality was handed over by Algirdas to his son Karigaila, then passed on to Lugvania, the founder of the princely family of the Mstislavs . In 1386, a fierce battle took place on the territory of the principality , after Smolensk prince Svyatoslav Ivanovich unsuccessfully tried to besiege Mstislavl and return it to his principality. In the battle, Svyatoslav was killed, and his troops were defeated.

The Principality of Mstislavl was for a long time strategically important. Therefore, the Polish-Lithuanian monarchs pursued a flexible policy towards local princes, trying not to allow their transition under the rule of the Grand Principality of Moscow. During the Russian-Lithuanian war of 1500-1503, the territory of the principality was the area of military operations and was badly damaged. In particular, in the Battle of Mstislavl, the Lithuanian army was defeated, although the Russian voevoda could not take the city itself.

In August 1514, Prince Mikhail Ivanovich of Mstislavl, at the approach of the Russian army to Mstislavl, swore allegiance to Vasili III, but after the Russian defeat at Battle of Orsha, he returned to the Lithuanian prince. In 1526 the Principality of Mstislavl became a direct possession of Sigismund I Jagiellon and was subsequently transformed into an old age. In 1566 in the territory of the former principality Mstislavl province was created.