In Roman Egypt, Hydreuma (plural hydreumata) was an enclosed (and often fortified) "watering station" along trade routes in dry regions. A hydreuma was a manned and fortified watering hole or way station along a caravan route, providing a man-made oasis.
The term Hydreuma only refers to wells, not to any other source of water. Water-tanks were known as hydreia or lakkos; technically the term hydreuma wasn't being applied to these forts.[1] An example of the other usages of the term "hydreuma" are the water basins of Roman era-Kharga Oasis[2] and outlying parts of villages with wells there.[3] The Arabs called these Roman fortified wells dêr (monastery), kariyah (village) or diminutive kurêyah or wekâla (caravanserai).[4]
Hydreuma are fortified water supply posts in the Eastern Sahara. According to Strabo they had wells or cisterns:[5]
Apart from water supply, they might have been used as trading monitoring posts for tax collection purposes, as garrisons and also as military-representative structures.[17] Some hydreumata were used as water sources to irrigate land,[18] and to supply water for the port of Berenice Troglodytica (Berenike).[19] The fortifications served to protect the well from desert sand.[20]
These forts are attested by Pliny, in texts found through the Eastern Desert,[1] reports of individual transports,[21] as well as in the Antonine Itinerary and the Tabula Peutingeriana.[22] While Strabo mentions that the first ones were built by Ptolemy II,[23] most were built by the Romans between the first and second century AD on the old Egyptian routes between the Nile Valley and the Red Sea,[5] after the earlier Ptolemaic trade route between Edfu and Berenike was largely abandoned.[24] Reportedly, Emperor Vespasian fortified many hydreumata, which thus became praesidia,[1] presumably because indigenous people began to use camels for raids.[22] They were later often repaired or reconstructed. Today many are either destroyed or buried by sand,[25] some were restaurated in the early 20th century.[26]
They are found along the old roads that lead to Berenike and Myos Hormos. These ports were part of the Roman-Indian trade routes and were active during the era of the early Roman Empire, when as many as hundred ships departed from Berenike every year,[27] and are mentioned in ancient accounts like the Periplus of the Erythraean Sea.[15] Traffic through these routes increased after the discovery of the monsoon winds[28] and was mostly by caravan, without wagons.[7] These ports were not self-sufficient, instead relying on supplies brought to them overland from the Nile Valley, as contemporary records indicate.[29] The roads were not paved nor did they feature milestones, sometimes they were not even cleared of rocks on the roadway.[30] Numerous branch roads connected the roads with each other and with sites like quarries.[31] Caravans on average would have reached each hydreuma after two days from the last one;[32] Strabo reports that some travel occurred during night.[33]
The two roads to Berenike and Myos Hormos have distinct hydreuma architectures, which may be due to them having different strategic importance to the Romans,[32] as the Koptos-Myos Hormos route may have doubled as an internal military border.[34] Additionally, there are non-hydreuma buildings along the roads,[35] as well as gold mines.[36]
Among the hydreumata are:
Other small hydreumata lie along the Edfu (Apollonopolis Magna[28])-Berenike road at Abbad, Abu Rahal, Abu Midrik (24°55.20′N 33°40.84′E / 24.92000°N 33.68067°E[40]), Rod al-Legah, Seyrig and Umm Gariya.[41] Their occurrence has been reported from west of the Nile as well,[42] in particular late Roman oasis fortifications,[43] but not from Numidia.[44] In the Libyan Desert, Roman-era centenaria resemble hydreumata[45] but were fortified grain-houses.[46]