The key to understanding the Pharsalia lies precisely in its highly intertextual character and its seemingly fragmentary structure, as it contains informal compositional units that are independent of the poems formal division into books. At one and the same time, therefore, the epic is both chaotic and very neatly ordered. The goal of the present study is to discover just how this informal division operates by analysing its basic elements, the way in which they are connected and - of course - their meaning.