The histories of the three duchies examined in this study exhibit certain parallels, chief among which is the fact that all three came to be ruled by single, powerful clans for all or part of the period between 850 and 1050. We know something of the background of the ducal dynasties of Amalfi and Naples; these will be examined later in this chapter. Very little, however, has previously been written about the family who came to power at Gaeta in 867. This is partly due to the fact that they have no known history before their emergence in the Gaetan documentation. Who were they and how did they come to power? Was their rise similar to that of the ruling families of contemporary neighbours?

From the main source of documentary material for Gaeta in this period, the Codex Cajetanus, it emerges that a man named Docibilis appears to have taken control in 867. His family were to dominate the castle and its territory for some 150 years. In the following discussion, I shall examine the evidence from the Codex and other sources to build up a more detailed picture of the beginnings of Docibilan rule.

In 839 one Constantine son of Anatolius received from his sister Elizabeth and her son-in-law Theodosius, prefect of Naples, two landed estates at a rent in kind which had to be delivered to Naples. The document recording the transaction was witnessed by Constantine's son Marinus.