The organic residues of lining in transport vessels from the Red Sea coast of Eritrea: a further element to understand past commercial relations

The archaeological site of Adulis lays on the Red Sea Coast of Eritrea and during Late antiquity played a significant role in interregional commerce among the Mediterranean, the Red Sea and the Indian Ocean coasts. Contacts with the Eastern Mediterranean, Arabian Peninsula and the Sasanian world have been attested from different classes of pottery that were brought to light from on-going excavations at the site. Transport vessels have attracted particular attention as they testify the extent of trades and exchange networks. Transport vessels were coated by organic materials to seal porosity and make them suitable to transport different liquids and/or food. The characterisation of coating materials helped shedding light on their function, and support the attribution to different classes of transport vessels found in the Indian Ocean and Red Sea worlds. Here, the characterisation of the organic lining detected on a set of samples identified as Late Roman Amphora 1 is discussed. Results from the chemical analyses, performed preliminarily by FT-IR and then by GC-MS, revealed that bitumen was used for lining the jars, thus leading to set the classification of the amphorae within the wide class of the so- called Torpedo jars. By overcoming the question of typological complexity posed from macroscopic examination of the sherds, the chemical investigation contributed here crucial information for the interpretation of past trading in the Indian Ocean. The research gave clues to broaden the distribution of the Torpedo jars to Adulis, giving an unexpected insight into the trading routes of the past.