Novgorod was a city in northern Rus', where the first masonry churches were built in the middle of the eleventh century. The Mongol invasion of 1238-40 became a watershed in the history of the architecture of Early Rus'. A change can be observed in construction practices - Novgorodian builders of late thirteenth century started to use large size and shape "bar bricks" instead of 'plinthoi' of the Byzantine type. The bricks of the bar type were the main ceramic building material up to the end of the fifteenth century. The source of this new type of brick is the early Gothic architecture of the Baltic region. The existence of a large number of dated monuments of Novgorodian architecture from the late thirteenth to fifteenth centuries allows us to form an idea of the development of production technology and the evolution of the size of Novgorodian bricks over that time. Characteristics of the moulding and the size and shape of bricks make it possible to date the masonry found during archeological work. The bricks of late thirteenth-fifteenth centuries are compared with the Novgorodian tradition of the pre-Mongol era and the bricks used in the Gothic architecture of the Baltic Sea countries.