Pelusium, titular metropolitan see of Augustamnica Prima in Egypt, mentioned in Ezech., xxx, 15 sq., (A. V. Sin), as the strength or rampart of Egypt against his enemies from Asia, which clearly outlines the eastern frontier of the Delta. Sin in Chaldaic, and Seyan in Aramaic, means mire, like the Greek Pelousion, which is a translation of it and which, according to Strabo (XVII, i, 21), refers to the mire and the marshes which surrounded the town. The latter was very important, being on the route of the caravans from Africa to Asia, also because its harbor joined the sea to the branch of the Nile called Pelusiac. The Pharaohs put it in a good state of defense. Among its sieges or battles were: the expedition of Nabuchodonosor, 583 B.C.; that of Cambyses who stormed it, 525 B.C. (Herod., III, 10-12); that of Xerxes, 490 B.C., and of Artaxerxes, 460 B.C.; the battle of 373 B.C. between Nectanebus King of Egypt, Pharnabazus, Satrap of Phrygia, and Iphicrates, general of the Athenians. In 333 B.C. the city opened its gates to Alexander; in 173 B.C. Antiochus Epiphanes triumphed under its walls over Ptolemey Philimetor; in 55 B.C. Anthony captured it; and in 31 B.C. Augustus occupied it. The Shah Chosroes took it in A.D. 616, Amru in 640; Baldwin I King of Jerusalem burned it in 1117. The branch of the Nile became choked up and the sea overflowed the region and transformed it into a desert of mud. A hill, covered with ruins of the Roman or Byzantine period and called Tell Farameh, marks the site. There are also the ruins of a fort called Tineh.
The first known bishop is Callinicus, a partisan of Meletium; Dorotheus assisted at the Council of Nicaea; Marcus, Pancratius, and Ammonius (fourth century); Eusebius (first half of the fifth century); George (sixth century). Pelusium became the metropolitan see of Augustamnica when that province was created, mentioned first in an imperial edict of 342 (Cod. Theod., XII, i, 34). The greatest glory of Pelusium is St. Isidore, d. 450. Under the name of Farmah, Pelusium is mentioned in the “Chronicle” of John of Nikiu in the seventh century (ed. Zottenberg, 392, 396, 407, 595).