The thesis is a contribution to the research area music archaeology, which lies in the intersection between musicology and archaeology. A catalogue with records of more than 800 individual jew's harps from archaeological contexts form the material basis of the thesis. The objects are collected from various museums and archaeological institutions in Europe.The United Kingdom (173 specimens), Switzerland (137) and Sweden (118) account for the largest numbers of jew's harps found in the earth, followed by the Netherlands, Germany and France. The material dates to the late medieval and post-medieval period. Some vague sources from various European countries suggest that the Romans, Saxons and Vikings knew the instrument. This thesis concludes, however, that the oldest specimens found in datable contexts are from around 1200 AD.In the 14th and 15th centuries the instrument became very popular, with a very wide geographical distribution. The manufacture had the character of mass production. The popularity was accompanied by a variety of forms. An important part of the thesis focuses on technology and typology, seeking to find some order behind the morphological diversity. Among the results, the analyses demonstrates that there was a typological development from jew's harps with small bows and long arms towards instruments with large open bows and short arms.Various iconographical and written sources suggest that the jew's harp predominated in the lower social strata. Depictions of the instrument from the 15th century and later show that its place was among travelling pedlars, minstrels and jugglers, as well as fools and beggars. It is not included among the instruments of professional minstrels.As many as 275 specimens, or one third of the material, were found in castles. It is very likely that these instruments belonged to soldiers, who played the jew's harp in their spare time. Since this was the great period for mercenaries in Europe, the soldiers probably had the instruments with them on their postings. Characteristically, the Italian name of the instrument is Scacciapensieri, meaning the dispeller of thoughts or worries.