When on 17 March 1420 the first of a series of crusades against the allegedly heretic Czech Hussites was solemnly proclaimed, this meant not only that from that moment on every true Christian was to fight the alleged heretics. By force of canon law every Christian was as well forbidden to further entertain commercial relations with his “heretic” Czech neighbours. This paper intends to present a complex view of this anti-Hussite trade embargo and to assess its role in the wider picture of 15th century Central European economic history: How did the embargo effect and transform Bohemia’s traditional position in the economic and social system of Central Europe? How does it relate to changing patterns of international trade such as the shifting of trade routes? Furthermore, special attention will be given to the question what effects – if any effects at all – the embargo had on the ground. Given the limits of pre-modern statehood, a total blockade was virtually unattainable. As previous research has shown, the embargo was in all likelihood continuously compromised. If this was the case, why did Catholic ecclesiastical and lay authorities not cede to propagate it? What advantages did they draw from promoting the embargo against the Czech Hussites? And how did those, who were expected to execute it on the ground, see the embargo?