This chapter discusses how and why Dionysius wrote the earliest history of Rome at such length. Dionysius’ own remarks on the writing of history, in both his theoretical treatises and the Roman Antiquities, are examined in order to show how they do much to explain this expansiveness, and two episodes (5.1.1–13.5; 5.52.1–57.4) that may serve as a general illustration of his techniques are analysed. Some suggestions are made as to where in the Roman annalistic tradition Dionysius found the material that allowed him to write at such length (it is argued that the lost history of Gnaeus Gellius was important). The chapter ends with discussion of a battle-scene (8.64.3–65.6) that exhibits characteristic Dionysian or Roman annalistic expansion. Throughout comparison of the Roman Antiquities with Livy’s Ab urbe condita, the only other extended narrative of early Rome that survives, is used to illustrate Dionysius’ techniques.