In Roman Egypt, a Greek, Ancient (to 1453);: hydreuma (plural Greek, Ancient (to 1453);: 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 Greek, Ancient (to 1453);: Hydreuma only refers to wells, not to any other source of water. Water-tanks were known as Greek, Ancient (to 1453);: hydreia or Greek, Ancient (to 1453);: lakkos; technically the term Greek, Ancient (to 1453);: hydreuma wasn't being applied to these forts. An example of the other usages of the term "hydreuma" are the water basins of Roman era-Kharga Oasis and outlying parts of villages with wells there. The Arabs called these Roman fortified wells Arabic: dêr (monastery), Arabic: kariyah (village) or diminutive Arabic: kurêyah or Arabic: wekâla (caravanserai).
Greek, Ancient (to 1453);: Hydreuma are fortified water supply posts in the Eastern Sahara. According to Strabo they had wells or cisterns:
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. Some Greek, Ancient (to 1453);: hydreumata were used as water sources to irrigate land, and to supply water for the port of Berenice Troglodytica (Berenike). The fortifications served to protect the well from desert sand.
These forts are attested by Pliny, in texts found through the Eastern Desert, reports of individual transports, as well as in the Antonine Itinerary and the Tabula Peutingeriana. While Strabo mentions that the first ones were built by Ptolemy II, 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, after the earlier Ptolemaic trade route between Edfu and Berenike was largely abandoned. Reportedly, Emperor Vespasian fortified many Greek, Ancient (to 1453);: hydreumata, which thus became Latin: praesidia, presumably because indigenous people began to use camels for raids. They were later often repaired or reconstructed. Today many are either destroyed or buried by sand, some were restored in the early 20th century.
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, and are mentioned in ancient accounts like the Periplus of the Erythraean Sea. Traffic through these routes increased after the discovery of the monsoon winds and was mostly by caravan, without wagons. These ports were not self-sufficient, instead relying on supplies brought to them overland from the Nile Valley, as contemporary records indicate. The roads were not paved nor did they feature milestones, sometimes they were not even cleared of rocks on the roadway. Numerous branch roads connected the roads with each other and with sites like quarries. Caravans on average would have reached each Greek, Ancient (to 1453);: hydreuma after two days from the last one; Strabo reports that some travel occurred during night.
The two roads to Berenike and Myos Hormos have distinct Greek, Ancient (to 1453);: hydreuma architectures, which may be due to them having different strategic importance to the Romans, as the Koptos-Myos Hormos route may have doubled as an internal military border. Additionally, there are non-Greek, Ancient (to 1453);: hydreuma buildings along the roads, as well as gold mines.
Among the Greek, Ancient (to 1453);: hydreumata are:
Other small Greek, Ancient (to 1453);: hydreumata lie along the Edfu (Apollonopolis Magna)-Berenike road at Abbad, Abu Rahal, Abu Midrik (24.92°N 73.84°W), Rod al-Legah, Seyrig and Umm Gariya. Their occurrence has been reported from west of the Nile as well, in particular late Roman oasis fortifications, but not from Numidia. In the Libyan Desert, Roman-era Latin: centenaria resemble Greek, Ancient (to 1453);: hydreumata but were fortified grain-houses.