The Grand Duchy of Lithuania and Duchy of Masovia between the second half of the 13th century and the first half of the 14th century: from dynastic diplomacy to territorial integration

The 13th century marked the beginning of the consolidation of the Lithuanian state: the ruling family, which could not be equalled in power, was dissolved, the territories under its control consolidated its dominance in Lithuania, and the social ties that were being established were based on the consolidation of military power. However, an equally important element in this process was the establishment of dynastic diplomatic ties, whereby marriages made it possible to forge alliances and thus maintain stronger ties. Considering that there are no known cases of polygamy among pagan Lithuanians, marriage as a diplomatic tool was one of the best ways to achieve stable ties both within the society and in their contacts with the surrounding Christian world. Already in the 13th century, information about the Lithuanian nobility shows that the tribal aristocracy had intermarried with each other through marriage, thus creating a stable network of relationships. From the beginning of the 13th century onwards, we know that Lithuanian dynastic diplomacy was effective, and it was rational to expand influence in this way. The centres where the Lithuanian tribal aristocracy established contacts turned into allies for military expansion into distant territories. This model also helped the spread of Lithuanian influence in the Ruthenian lands. The dynastic diplomatic ties with the Galycian-Volhynian state created the preconditions for the formation of new forms of political culture. In Novagrudok, a condominium was created between Lithuania and the Galycian-Volhynian state, where the ruling prince was the son of the Galycian king, but his brother married the daughter of the Lithuanian king. There is a lack of data on how the Lithuanians took control of the Duchy of Polotsk, but the Prince who ruled there, Tautvila (nephew of King Mindaugas of Lithuania), also had a dynastic relationship with the ruler of the Gallician-Volhynian state, Danylo Romanovich, who was married to Tautvila's sister, and therefore took control of the Duchy of Polotsk with his help. Thus, already from the 13th century Lithuanians began to use dynastic diplomacy in the process of consolidation and development of the state. Lithuanian relations with the Duchy of Masovia began in 1262. At that time, Masovia was one of the domains of the Piast dynasty, which was quite independent in the Polish political landscape, especially as the Polish Piast system itself had reached a high level of disintegration at that time, and the political, social and communication channels between the individual Piast domains were lacking and were not constant. The first contact between Lithuania and Masovia in 1262 was of a military nature, the Lithuanians invaded Masovia and plundered a large territory. The Masovian prince Siemovit I was killed in the clash. Already in 1279, Prince Boleslaw II of Masovia, the son of Siemovit I, married Gaudemunda, the daughter of Lithuanian ruler Traidenis. This became a traditional line of dynastic diplomacy for Lithuanian rulers. At the beginning of the 14th century, this form of diploamthy became traditional: in 1305, Prince Wenceslas of Masovia married Gediminas' daughter Elizabeth, and in 1331, another Masovian prince, Boleslaw Jurij of Masovia, married Euphemia, also a daughter of Gediminas. A whole tradition of intermarriage between the rulers of Masovia and Lithuania was established, which continued until the mid-15th century. Elements of dynastic diplomacy became important in the 13th and 14th centuries, when the rulers of Masovia established themselves in the Galycian-Volhynian state, for which the rivalry intensified in 1341, when Boleslaw Jurij, who had been ruling it, died. The main focus of this report is the issue of dynastic diplomacy, which allowed first the preparation and later the integration of the territories into the emerging Grand Duchy of Lithuania. It will also present other important Lithuanian models of action that allowed the development of dynastic diplomacy