Reconstruction and restorations of Ventspils Palace was initiated in 1995 and it was necessary to choose appropriate restoration materials. Ventspils Palace was made from brickwork. The major causes of damages in the structure of historical bricks are: migration of the water-soluble salts, and frost influence during wintertime - mechanic damage of structure by crystallization and growing of salts or ice crystals. There is an increased corrosion of single brick or brick masonry fragments in the architectural monuments of the Middle Age observed. There is a necessity to replace these bricks with the new ones of the same size, color and physical properties. The aim of the research is to characterize the historical bricks taken from Ventspils palace and to again knowledge of historical manufacturing process.