State and political institutions evolved with increasing speed in the grand duchy of Lithuania throughout the fourteenth and fifteenth centuries. In the fourteenth century the power of the grand duke was based on inheritance, in the sense that he gained it by being the son of his father generally acknowledged as most fit to rule. The members of the dynasty had the right to be endowed with their hereditary lands under the grand duke’s lordship. In the areas which were directly subject to him, the grand duke was absolute ruler and governed personally as leader and judge, although he received help from his court and his lieutenants in particular territories. In regions granted as duchies to members of the dynasty, or in those duchies where Rus'ian princes were installed, the duke was likewise an absolute ruler.
The boyar class comprised knights owing military service. It occupied lands distributed by the grand duke or regional duke which were heritable in the male line but subject to confiscation at the ruler’s will. The population of boyar villages owed tribute and service to the grand duke on his lands or to the dukes on theirs. Apart from the free population of serfs subject to the boyars, there were also slaves, particularly enslaved prisoners of war.
In the fifteenth century privileges, which sometimes reflected the influence of Polish law issued by the grand dukes both for the grand duchy as a whole and for particular lands within it, helped to achieve new models of social relationships and institutions. There can be no doubt that the granting of such privileges resulted in the creation of a social structure more widely differentiated than before. In the course of the century, certainly by the time of the death of Vytautas, individual princes lost their lands to the grand duke who conferred them on a more limited basis. These princes were transformed from regional rulers into members of the upper class in which they joined the boyars who were termed lords and who formed a strong, propertied group. They were leaders with their own banners, and stood responsible only to the grand duke as judge. The remaining mass of boyars created a gentry differentiated by property. While a section of the gentry enjoyed the privileges granted to the boyar-lords (inherited property, no punishment without trial, the consolidation of tax and personal dues), there were also boyars of the second rank who were subject to a prince or lords.
The peasant population consisted of those born as slaves who, as household servants, were deprived of all rights even when settled on manors and lands, and of serfs, who did have a legal identity, although they were bound to the soil. At the same time a considerable number of freemen enjoyed personal freedom but lacked property rights.
The towns in Lithuanian Rus' maintained their old structures, having a free population with differentiation between the richer denizens, who owed cavalry service, and the rest. In legal matters the towns were dependent on the grand-ducal or ducal lieutenants and their judiciary. From the end of the fourteenth century, with ducal agreement, a few towns (Vilnius and Trakai) came under German law: but there were still only a few of these in the fifteenth century. The network of towns with either local or German law became very rare. This is typical of eastern Europe, but contrasts with the situation in central and Baltic Europe.
Jews appeared in Lithuania by 1388, and more came in the next century to occupy urban settlements. They received three local charters from Grand Duke Vytautas (1388—9) which were confirmed as general privileges by King and Grand Duke Sigismund in 1507. The small number of Tatar military settlements on the territory of the grand duchy (from the second half of the fourteenth century) enjoyed full recognition of their Islamic confessional allegiance. In Vytautas’s day, a small group of Karaites arrived in Lithuania to practise Judaism without Rabbinical or Talmudic teachings.
From 1440, when the Lithuanian lords elected Prince Casimir as their ruler, the office of grand duke became elective, although always limited to descendants of Wladyslaw II Jagiello. The grand duke exercised his authority with the help of court dignitaries of whom the chancellor (from 1458 always palatine of Vilnius at the same time) exercised wide authority in domestic and foreign affairs. Lieutenants controlled provincial administration and eventually, under Polish influence, these came to be called starostas, holding full financial and judicial powers. From 1413 onwards there were two voivodships, or palatinates: Vilnius and Trakai, with another centred on Kiev after 1471, along with the castellanies of Vilnius and Trakai. At the district (powiat) level the leaders were the standard bearers, that is gentry captains summoned to regional mobilisation.
Political society was constituted by the grand-ducal council. This included bishops, court and provincial officials, in total several dozen persons. Alongside this council was a more prescribed or secret council consisting of a handful of lords. These were advisory bodies with great political power which, from the mid-fifteenth century, were consulted regarding the levying of taxes. The summons of the grand-ducal council in 1492, directing each province to send ten or more representatives to the election of the new grand duke, led to the establishment of a Lithuanian sejm. However, like that of the land diets, the full development of the sejm was to occur in the sixteenth century.