When _Cyrus_ took _Babylon_, he changed the Kingdom into a Satrapy or Province: whereby the bounds were long after known: and by this means _Herodotus_ [426] gives us an estimate of the bigness of this Monarchy in proportion to that of the _Persians_, telling us that _whilst every region over which the King of _Persia_ Reigned in his days, was distributed for the nourishment of his army, besides the tributes, the _Babylonian_ region nourished him four months of the twelve in the year, and all the rest of _Asia_ eight: so the power of the region_, saith he, _is equivalent to the third part of _Asia_, and its Principality, which the _Persians_ call a _Satrapy_, is far the best of all the Provinces_. _Babylon_ [427] was a square city of 120 furlongs, or 15 miles on every side, compassed first with a broad and deep ditch, and then with a wall fifty cubits thick, and two hundred high. _Euphrates_ flowed through the middle of it southward, a few leagues on this side _Tigris_: and in the middle of one half westward stood the King's new Palace, built by _Nebuchadnezzar_; and in the middle of the other half stood the Temple of _Belus_, with the old Palace between that Temple and the river: this old Palace was built by the _Assyrians_, according to [428] _Isaiah_, and by consequence, by _Pul_ and his son _Nabonassar_, as above: _they founded the city for the _Arabians_, and set up the towers thereof, and raised the Palaces thereof_: and at that time _Sabacon_ the _Ethiopian_ invaded _Egypt_, and made great multitudes of _Egyptians_ fly from him into _Chaldæa_, and carry thither their Astronomy, and Astrology, and Architecture, and the form of their year, which they preserved there in the _Æra_ of _Nabonassar_: for the practice of observing the Stars began in _Egypt_ in the days of _Ammon_, as above, and was propagated from thence in the Reign of his son _Sesac_ into _Afric_, _Europe_, and _Asia_ by conquest; and then _Atlas_ formed the Sphere of the _Libyans_, and _Chiron_ that of the _Greeks_, and the _Chaldæans_ also made a Sphere of their own. But Astrology was invented in _Egypt_ by _Nichepsos_, or _Necepsos_, one of the Kings of the lower _Egypt_, and _Petosiris_ his Priest, a little before the days of _Sabacon_, and propagated thence into _Chaldæa_, where _Zoroaster_ the Legislator of the _Magi_ met with it: so _Paulinus_, _Quique magos docuit mysteria vana Necepsos_: