The Harbour of Kaisarius (Λιμὴν τοῦ Καισαρείου) is mentioned for the first time in the Acts of the Fifth General Council of Constantinople,[[1136]] 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,[[1137]] in what is manifestly a quotation from Theophanes.[[1138]] Beside it stood a district,[[1139]] and a palace,[[1140]] 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[[1141]] 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;[[1142]] 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.[[1143]]
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,[[1144]] in his biography of Basil I., by whom the church was restored: secondly, Cantacuzene[[1145]] employs the phrase to indicate the situation of the harbour now under discussion.
In 1351 Cantacuzene[[1146]] 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.[[1147]]
Du Cange,[[1148]] misled by the fact that a Church of St. Acacius was found in the Tenth Region—one of the Regions on the northern side of the city—has classed the Neorion at the Heptascalon among the harbours on the Golden Horn. But to identify a site in Byzantine Constantinople by means of a church alone is a precarious proceeding, for churches of the same dedication were to be found in different quarters of the city. This, Du Cange[[1149]] himself admits, was possible in the case before us; since, besides the Church of St. Acacius at the Heptascalon, writers speak of a Church of St. Acacius ad Caream (Ἐν τῇ Καρύᾳ), and the identity of the two sanctuaries cannot be assumed. But the existence of a second church dedicated to St. Acacius is not a mere possibility. According to Antony of Novgorod,[[1150]] there was a church of that dedication also on the southern side of the city, not far from the Church of SS. Sergius and Bacchus. The Neorion at the Heptascalon may, therefore, have been on the Sea of Marmora.
And that it was there, as a matter of fact, is evident from the statements made regarding that harbour by Cantacuzene and Nicephorus Gregoras, in their account of the naval engagement fought in the Bosporus in 1351, between a Genoese fleet on the one hand, and the Greeks, supported by Venetian and Spanish ships, on the other.
Upon coming up from the Ægean to take part in the war, the Venetians and the Spaniards, says the former historian,[[1151]] anchored off the Prince’s Island, to rest their crews after the hardships of the winter. There they remained three days. Then, quitting their moorings, the two allies made for the Neorion at the Heptascalon, or, as it is also styled, the Neorion of the Byzantines (τὸ Βυζαντίων νεώριον),[[1152]] to join the Imperial fleet which was stationed there, all ready for action, and awaiting their arrival. Meanwhile, the Genoese admiral, with seventy ships, had taken up his position at Chalcedon (Kadikeui), to watch and oppose the movements of the allied squadrons. The wind was blowing a gale from the south, and though the Venetians and Spaniards had started for the Heptascalon very early in the morning, it was with the utmost difficulty, and late in the afternoon, that they succeeded in crossing from the island to the city. Even at the last moment they narrowly escaped destruction, by being dashed to pieces against the boulders scattered along the foot of the walls as a breakwater.
The Byzantine admiral, encouraged by the arrival of his allies, then sallied forth from the Heptascalon, and led the way towards the Genoese ships at Chalcedon. The latter, finding it impossible to make head against the wind, retired towards Galata, and skilfully entrenched themselves among the shoals and rocks off Beshiktash, preferring to be attacked in that advantageous situation.[[1153]] The allies came on, and a desperate conflict, partly on the water, partly on the rocks, ensued, until night parted the combatants without a decisive victory on either side.
With this narrative of Cantacuzene in view, no one familiar with the vicinity of Constantinople can doubt for a moment that the Neorion at the Heptascalon was upon the Sea of Marmora. The single circumstance that the walls in the neighbourhood of the harbour were protected by boulders placed in the sea as a breakwater is alone sufficient to prove the fact; for only the walls bordering the Sea of Marmora were defended in that manner. Equally conclusive is the circumstance that the Venetian and Spanish ships found it difficult to make the harbour from the Prince’s Island with a strong south wind on their left. Such a wind would drive them towards the Bosporus with a violence that would render it almost impossible for them to put into any port on the Marmora shore of the city. Nor is it less decisive to find, as the historian’s account makes perfectly clear, that the harbour was so situated; that the approach to it, and possible shipwrecks at its entrance, could be observed by the Genoese admiral stationed off Chalcedon; that an enemy at Chalcedon found it hard to advance towards the Heptascalon in a strong south wind; and that vessels proceeding from the harbour to Galata could, on the way, touch at Chalcedon. These facts hold true only of a harbour on the Sea of Marmora.