As its title suggests, this study falls into two parts. The purpose of the first part is to assess the character of Cato's lost historical work. I have tried to refute the prevalent opinion that the Origines was a posthumous compilation of two or more separate works (Chapter I), and to explain why Cato omitted the early history of the Republic and wrote instead about the origins of Italy (Chapter II). Chapters III and IV contain a more detailed study of the form and content of the individual books of the Origines, while Chapter V examines the notion that Cato's account of Italian origins was inspired by a branch of Greek literature concerned with foundations. (Detailed evidence about the Ktiseis is presented at the end of the thesis in Chapter XI). The second part of the thesis investigates the sources used by Cato in his Italian researches. Cato was the first writer to make a serious study of the earliest history of peninsular Italy. Previous researchers had not done his work for him, and I have argued that his account was founded on a first-hand study of the primary evidence (Chapter VI). A large amount of historical evidence in the form of oral tradition, documents and literature would have been available to Cato in the communities of non-Roman Italy. The extent and character of this material, collectively labelled "the non-Roman historical tradition", is illustrated by the test case of the Etruscans. Chapters VII and VIII are devoted to a wide-ranging study of Etruscan historiography and other kinds of historical tradition in Etruria. Finally, taking as specific examples his researches into the history of Campania (Chapter IX) and the origin of the Sabines (Chapter X), I have tried to show more precisely how Cato made use of indigenous sources.