The article develops a new definition of conspiracy theory more apt for historicizing purposes than the existing systematic and philosophical ones. It shows that modern conspiracy narratives do appear only with the Renaissance. Also, ‘security‘ as the aim of state and international politics became important only now during the Italian Renaissance while the term and concept had been nearly forgotten during the Middle Ages. The article shows then that both, security politics in practice and political language as well as modern conspiracy narratives belong to the new type of political communication which emerged with inter-territorial diplomacy in 15th century Italy (example: Lorenzo de‘ Medici) and with the first emerging information public sphere in 16th century Europe (example: conspiracicsm during the French Wars of Religion). The narrative modus of analyzing the present state of affairs, of constructing reality and of planning and conjecturing in that form of political communication is highly similar to the construction of conspiracy narratives. All modern forms of opposition between security and conspiracy theories can be seen as derivatives of that Renaissance constellation.