The Bronze Age hillforts of Lossow and Lebus are our point of departure to discuss the phenomenon of multiple fortifications. This paper provides an introduction to the topic and summarizes the results of a Topoi workshop on this subject. Multiple fortifications are separated fortifications of two or more that are spatially proximate to one another and contemporaneous, making them a functional unit. This paper discusses the research objectiveas well as a possible classification of multiple fortifications. The research problems receivespecial focus, of which the proof of contemporaneity appears to be the most serious problem.