Mategosan archaeology indicates the earliest formal settlements began around the 9th Century BCE. A few fishing settlements of the Delmatae tribe, identified by their burial methods and a shrine to Vidasus, bear witness to the earliest permanent inhabitants of the Mategosan islands. Later, as a result of the Great Illyrian Revolt, the Romans sent in colonists from Latium to settle and pacify the islands as part of a larger move to incorporate the province of Illyricum.

Mategosa was seen as a strategic hold in the Adriatic on the main route for shipping Dalmatian gold back to Rome. Cassius Dio noted that Mategosa provided a watchful eye over the ships carrying the gold. In his typical cynicism, Cassius Dio also commented on how Mategosa also seemed to have an outstretched hand to collect any parts of those shipments that went astray.

There was no overt brigandage or piracy in these transactions: although the ancient records are sparse on these matters, what records we do have either hint or directly accuse the Mategosans of being part of a greater chain of financial arrangements, always with the implication that imperial treasuries were involved as partial beneficiaries of these diversions of gold, the Mategosan middle-men being the other party that answered the question, “cui bono?”

All of the Claudian emperors enjoyed the secrecy and creative accounting provided by their Mategosan citizens. The island itself, while ostensibly part of the province of Illyricum, had a special governor appointed to oversee the special administrative arrangements performed on the island. The nummularios (money-changers) of Mategosa would register the inbound shipments of gold by “reviewing” the cargo manifest of the ships. In reality, the Mategosans were making an identical copy of the manifest, bar a change on the amount of gold in the shipment. The doctored manifest would be returned to the ship after an appropriate amount of gold had been removed to true-up the figures.

The removed gold would then go on to the treasuries of both the Emperor and the nummularios of Mategosa. Over time, each of the family groups on Mategosa became involved in the gold traffic. The proceeds of their operations did not go to just one person, but were considered to be assets for each family as a whole. The Claudian period is where we see the development of the familial/clan social structure in Mategosa that persists to this day.

After the Claudians, there was a gap in imperial usage of the Mategosan connection. Dalmatian cargo was interrupted during the chaos of The Year of the Four Emperors and the Flavians did not renew the system favored by the Claudians. Trajan, however, revived the old gold route, along with the diversion on the docks of Mategosa harbor. Commodus neglected the arrangements and the lack of private finances is considered to be a contributing factor to the instability of his regime. Septimus Severus worked with the Mategosans, but is an exception in the regnal list for many years, as the Empire became more chaotic and the Crisis of the Third Century commenced.

The reign of Gallienus was a period of governmental stability in the 3rd Century, even if the frontiers of the Empire were fraying and regional governors were often rebelling. Gallienus visited Illyricum several times between 253 and 258 and stopped at Mategosa more than once: it is unclear if the islanders were able to convince the Emperor to take advantage of their services. Given that the economy collapsed during the later years of his reign, it is unlikely that he did. Or, if he did, he did not make effective use of such services.

What we do know is that the gold began arriving again at Mategosa during the 260s. From the transactional records we have, we can determine that once again the Mategosans were changing manifests, but they do not seem to have included the Emperor in their arrangements. In the turmoil of the next 20 years, the Emperors forgot completely about Mategosa. By the time of Julius Nepos in 474-480, the Dalmatian coast was accountable to the Emperor only because he lived there. After the fall of Julius Nepos, Mategosa fades from history with the rest of the Dalmatian coast. But the gold, hidden away in the underground cavern systems of Mategosa, never lost its luster. As trade and banking returned to the region following the establishment of the Byzantine theme of Dalmatia and the Kingdom of Croatia, Mategosa was ready to provide the secrecy and special arrangements that are often attached to that industry.