During his reign, King Sigismund of Luxemburg (1387-1437) awarded the loyalty of his followers with different types of privileges; coats of arms were among the most popular. Up to this point no approach from social history has been applied for this source category. The aim of this interdisciplinary research is to study the phenomenon of granting nobles from Transylvania with grants of arms. On the basis of visual and written source material and secondary literature, the following questions are discussed: why was this privilege so popular, who could receive it and why, how do the coats of arms look like, and whether it can be stated that this award could assure good relations between royalty and nobility. The first part of the work examines the structure of the grant of arms, focusing on the elements of royal propaganda and on what kind of information can be derived from these documents. The following unit is dedicated to the grantees, by setting up a biographical gazetteer. The last chapter gives an analysis and heraldic description of the studied coats of arms, and a brief introduction in the characteristics of the Hungarian heraldry.