This paper discusses the role played by master at arms (Fechtmeister) in the fightschools (Fechtschulen) taking place in the Swiss towns at the end of the middle ages. The strong link between these less-studied events and the practice of martial arts according to the technical literature (Fechtbücher) will be examined, as well as the figure of the master at arms. By collecting references out of normative documents regarding those events, it is possible to sketch both the fighting praxis inside the fightschools and the expertise of the master at arms in relation with the town's authorities. Doing so, the questions of the professional performances, the reputation and the representation of the Fechtmeister will be addressed. This approach will be illustrated by the case study of a master at arms, Peter Switzer.