The article deals with the reconstruction and explanation of the measures of weights used in medieval East-Central Europe and in Ukraine and Belarus until the Modern Time — golovazhnya and voz. However, in the Muscovite State and Novgorod Land the golovazhnya did not use at the same scale; at least the historical documents do not mention it. The golovazhnya is mentioned by the Ruskaya Pravda and Kievo-Pechersk Patericon in the documents and the description of events of the second half — end of the 11th century. On the basis of the analysis of medieval texts and birch bark documents from Novgorod, the weight of the golovazhnya (caput salis, galwage) is calculated as circa 75 gr. The author also argues the identity of berkovets (Berkowitz or Schiffspfund of Germen medieval texts) and voz (cartful or currus), equal to 163,8 kg. The dynamic of prices for slat trade in Middle Ages, especially in Novgorod and Pskov in the 13th–15th centuries, is also evaluated. The author proposes a new interpretation of birch bark document N 219 from medieval Novgorod. This interpretation confirms earlier proposed hypothesis on the relationship between the Rus medieval monetary unit such as grivna, kuna and nogata. The potential of hagiography as a source for the study of medieval material culture is revisited