ENThere were only a few masonry castles in Lithuania, surrounding the territory from Kaunas to Gardinas (Grodno), Lyda (Lida), Krėva (Krėva), and Medininkai, the circle being closed by the complexes of Trakai and Vilnius castles. The beginning of brick castles in all the countries is therefore directly related to the emergence of the state and the development of its capacity, and the Grand Duchy of Lithuania is no exception. Historical annals have no references to the date when construction of the old brick castles started in Lithuania. The feasibility of these works in the embryonic stage of the state, and even after Mindaugas’ assassination, is questionable. Construction of Vilnius castles has been recently more and more often associated with the name of Traidenis (1269-1282) or Vytenis (1295-1315). It is an unquestionable fact, that as early as the very beginning of the rule of Gediminas (1316-1341) there were Lithuanian brick castles in at least the Old Trakai and Vilnius. Recent archaeological investigations at Medininkai castle, and especially the excavations at Krėva and Lyda castles, carried out by Belarussian archaeologists, also lead to an assumption that castles of this style, the so called enclosure castles, could have been built during the rule of Gediminas. They are similar in terms of form, defensive system, brickwork techniques and low, previously uninhabited location chosen as the construction site. It was most probably in this period, at the end of the 13th or beginning of the 14th century, when residences of Lithuanian sovereigns were built in Vilnius and Trakai.