Introduction

These pages are primarily a brief summary of a study by Siegfried De Laet that was published in 1949: a study of the archaeology and history of the portorium in the first three centuries AD. It was the first overall study of the topic after many years, superseding work by René Cagnat published in 1882. De Laet's work received many positive reviews. It is thorough, balanced and well-documented, and a pleasure to read. The summary is supplemented by some information from later studies, including new and sometimes even quite spectacular evidence.

The portorium was a right of passage, a transport tax collected on the circulation of merchandise. For easy reference we can speak of "customs duties", but the portorium covered more. It consisted mainly of customs duties, an import and export tax. Another component was the octroi, a tax levied by municipalities, with the permission of the Emperor, on the importation of goods into their territory. The third component was toll, to be paid at bridges etcetera. The tax was collected on the borders of the Empire, on the borders of large customs districts, and in the interior of these districts. It applied to sea, river and land transportation. In the Imperial period the word vectigal, "tax" in the widest sense, begins to become a synonym for portorium, eventually replacing it. Another word that was used to refer to the portorium is publicum, public revenue.

The portorium is mentioned for the first time for the year 508 BC, by Titus Livius (Ab Urbe Condita II,9,6). Some authors have suggested that the portorium was introduced by king Ancus Marcius in the seventh century BC, in relation to the founding of Ostia. That is mere speculation. The first reliable information concerns the second century BC.

The customs offices where merchandise was checked and the tax was collected were called stationes. The height of the portorium of the central customs duties was calculated ad valorem, which means that it was a fixed percentage of the value of the commodities, not a precentage that varied according to the nature of the commodities. Therefore we hear of quadragesima and quinquagesima, the fortieth and fiftieth part, so 2.5% and 2%. All goods were taxable, with the exception of personal belongings (ad usum proprium) and travelling gear (instrumenta itineris), such as wagons and the animals that pulled them. The octroi was not always calculated ad valorem: there could be specific rates for certain commodities. Goods belonging to the Emperor were exempt from taxes.

De Laet places an important phase in the development of the portorium in the reign of Tiberius. Large customs districts were created, each consisting of one province, several provinces, or parts of provinces. At first the tax was collected by private publicani, then by conductores ("contractors"), and eventually by Imperial officials. According to De Laet the entire revenue went to the fiscus, the private treasury of the Emperor, not to the aerarium Saturni, the treasury of the Roman people (this is disputed in the reviews by A.N. Sherwin-White and C.G. Starr, who argue that it did go to the treasury of the Roman people, but was placed at the disposal of the Emperor).

Bottom: dedication by Siegfried De Laet to prof. Willem Glasbergen.