The Harbour of Kaisarius (Λιμὴν τοῦ Καισαρείου) is mentioned for the first time in the Acts of the Fifth General Council of Constantinople,[1135] held in 553, under Justinian the Great. Near it, we are there informed, stood the Residence of Germanus: “In domo Germani, prope portum Cæsarii.” The harbour is mentioned for the last time by Cedrenus,[1136] in what is manifestly a quotation from Theophanes.[1137] Beside it stood a district,[1138] and a palace,[1139] known respectively as the District and the Palace of Kaisarius (ἐν τοῖς Καισαρείου: κυράτωρ τῶν Καισαρείου); the latter being probably the residence of Germanus above mentioned. After whom the harbour was named is uncertain. Du Cange[1140] suggests three persons from whom the designation may have been derived: Kaisarius, Prefect of the City under Valentinian; Kaisarius, Prætorian Prefect under Theodosius I.; and Kaisarius, a personage of some note in the reign of Leo I. If the choice lies between these persons, the preference must be given to the last; for the _Notitia_, which describes the city in the reign of Theodosius II., makes no mention of this harbour. In all probability, therefore, the Harbour of Kaisarius was constructed towards the close of the fifth century. That it stood on the Sea of Marmora is evident; first, from its association with the Harbours of Julian and of Hormisdas, as one of the points at which the tyrant Phocas placed troops to prevent the landing of Heraclius on the southern side of the city;[1141] and secondly, from the fact that it was there that Constantine Pogonatus, in 673, placed his ships, armed with the newly invented tubes for squirting Greek fire, to await the Saracen fleet coming up against the city from the Ægean.[1142] Passing next to the Neorion at the Heptascalon, we find that the term “Heptascalon” is employed by Byzantine writers only in two connections: first, and then generally in the corrupt form Πασχάλῳ or Πασκάλῳ, it serves to mark the site of a church dedicated to St. Acacius; the earliest writer who uses it for that purpose being Constantine Porphyrogenitus,[1143] in his biography of Basil I., by whom the church was restored: secondly, Cantacuzene[1144] employs the phrase to indicate the situation of the harbour now under discussion. In 1351 Cantacuzene[1145] found the harbour in a very unsatisfactory condition. Owing to the sand which had accumulated in it for many years, it could hardly float a ship laden with cargo; and accordingly, in pursuance of his policy to develop the naval resources of the Empire, he caused the harbour to be dredged at much labour and expense, to the great convenience of public business. So extensive was the work of restoration that in one passage the harbour is styled the New Neorion.[1146]