. Of the entire circuit the part on the land side reached a
great height so as to repel any who came that way: the portion next to the
sea was lower. There, the rocks on which it had been reared and the
dangerous character of the Bosporus were effective allies. The harbors
within the wall had both been closed with chains and their breakwaters
carried towers projecting far out on each side, making approach impossible
for the enemy. And, in fine, the Bosporus was of the greatest aid to the
citizens. It was quite inevitable that once any person became entangled in
its current he should willy-nilly be cast up on the land. This was a
feature quite satisfactory to friends, but impossible for foes to deal
with.

[Sidenote:--11--] It was thus that Byzantium had been fortified. The
engines, besides, the whole length of the wall, were of the most varied
description. In one place they threw rocks and wooden beams upon parties
approaching and in another they discharged stones and missiles and spears
against such as stood at a distance. Hence over a considerable extent of
territory no one could draw near them without danger. Still others had
hooks, which they would let down suddenly and shortly after draw up boats
and machines. Priscus, a fellow-citizen of mine, had designed most of
them, and this fact both caused him to incur the death penalty and saved
his life. For Severus, on learning his proficiency, prevented his being
executed. Subsequently he employed him on various missions, among others
at the siege of Hatra, and his contrivances were the only ones not burned
by the barbarians. He also furnished the Byzantines with five hundred
boats, mostly of one bank, but some of two banks, and equipped with beaks.
A few of them were provided with rudders at both ends, stern and prow, and
had a double quota of pilots and sailors in order that they might both
attack and retire without turning around and damage their opponents while
sailing back as well as while sailing forward.

[Sidenote:--12--] Many, therefore, were the exploits and sufferings of the
Byzantines, since for the entire space of three years they were besieged
by the armaments of practically the whole world. A few of their
experiences will be mentioned that seem almost marvelous. They captured,
by making an opportune attack, some boats that sailed by and captured also
some of the triremes that were in their opponents' roadstead. This they
did by having divers cut their anch