Clysma was founded or rebuilt by Emperor
Trajan in the second century AD to protect travellers and merchants as it lay at the junction of roads from Sinai, Palestine, and Egypt. This was done in conjunction with the construction of the
Amnis Traianus, a canal that linked the Nile and the Red Sea and had its outlet near Clysma. It has been suggested that the port was used for the exportation of textiles and grain produced in the
Arsinoite nome as they were better adapted to transportation via the
Amnis Traianus to Clysma than overland to the southern ports of
Berenice Troglodytica and
Myos Hormos. Clysma is first recorded in
Lucian's
Alexander Pseudomantis in the early 2nd century AD, and by
Ptolemy in
Geographia in the mid-2nd century, in which he described Clysma as a
phrourion. In 179, soldiers of the
Ala Veterana Gallica were stationed at the city. Clysma is also described in the works of
Hierocles as a
kastron, and is recorded in the
Panarion of Saint
Epiphanius of Salamis. As well as this, church historians
Eusebius in
Onomastikon and
Philostorgius in
Historia Ecclesiastica make reference to the city. Saint
Eugenios of Clysma is said to have studied as a monk at Clysma. The nearby
Mountain of Antony, also known as the Mountain of Clysma, was inhabited by
anchorites, such as Saint
John the Dwarf, and Saint
Sisoes the Great, who died there in 409 and 429, respectively. The destruction of the Nile emporium of
Koptos, from where goods were transported overland to Berenice and Myos Hormos, by Emperor
Diocletian in the late third century temporarily disrupted trade at the southern ports and led to an increase of trade at Clysma which reached its peak in the fourth and fifth centuries. A
commercius, an official with responsibility for foreign trade, was active at Clysma during the reign of Emperor
Anastasius I Dicorus. Clysma is recorded on the
Tabula Peutingeriana. In response to an appeal for aid, in c. 525, Emperor
Justin I had Clysma provide twenty vessels to the king of Ethiopia in his war with the king of
Himyar. The
Plague of Justinian likely first entered the Roman Empire through the port of Clysma, and thus spread to
Pelusium, where it was first reported in mid-July 541. According to
Eutychius of Alexandria, a church of Saint Athanasius was constructed at Clysma on the orders of Emperor
Justinian I. In c. 570, Clysma was visited by the
anonymous pilgrim of Piacenza, who noted eighteen or more tombs of hermits at the city's basilica. After the
Muslim conquest of Egypt, Clysma was known in Arabic as
al-Ḳulzum, and the
Red Sea was known as the Baḥr al-Ḳulzum (sea of Clysma). ==Ecclesiastical history==