The source material for this study is of two main types. Firstly, a large corpus of medieval charters, recording mostly land transactions, exists in published form, and has remained relatively unexploited as a source of information about life in this area between the ninth and the early twelfth centuries. This is despite the fact that it allows individual families to be examined in some detail. The landless and unfree, on the other hand, make only fleeting appearances in the documents. They never reached a level of wealth which allowed them a permanent presence in a written record that was concerned mainly with land transactions. And, as we shall see, even those who owned land sometimes seem not to have thought it necessary to write down all their transactions. Nevertheless, the material at our disposal is copious, and offers a valuable opportunity to piece together the lives of many inhabitants of the Tyrrhenian coast. The charters will be discussed in detail presently.

The second body of written evidence consists of letters and narrative sources, and is useful in creating a wider framework in which to set the detailed information from the charters. Apart from specific material relating to individual cities, several sources are relevant for a history of the South as a whole. They include letters of the popes, especially John VIII, and other material relating to the papacy's history and interest in its southern properties, including the Liber Pontificalis and the Liber Censuum.