EN
The authors examined the composition o f twelve samples o f mortar from the defensive binding o f brick walls in the Old Town in Warsaw. The researchers applied the X-ray method, thermal analysis and observations with an optical and scanning microscope. The composition o f the hardened mortar made it possible to determine the original composition. Two groups: lime and cement-lime were distinguished from the point o f view o f the composition o f the mortar in question. A characteristic feature o f the cement-lime mortar was the differentiated contents o f the binder. The relation between the binding and sand in this case oscillated from 1:1,8 to 1:6,2.