Tacitus histories “the Jews” book 5/ 12  The Gihon Spring in the temple!

12. The Temple was like a citadel and had its own walls, which had
been even more laboriously and skilfully constructed than the rest.
The porticoes around it constituted in themselves an excellent
defensive position. >>To these advantages must be added a spring of
never-failing water, <<<chambers cut in the living rock, and tanks and
cisterns for the storage of rainwater. Its builders had foreseen only
too well that the strange practices of the Jews would lead to
continual fighting. Hence everything was available for a siege,
however long. Moreover, after Pompey's capture of Jerusalem, fear and
experience taught them many lessons. So taking advantage of the
money-grubbing instincts of the Claudian period, they purchased
permission to fortify the city, and in the days of peace built walls
meant for war. Already the home of a motley concourse, its population
had been swollen by the fall of the other Jewish cities, for the most
determined partisan leaders escaped to the capital, and thereby added
to the turmoil. There were three different leaders and three armies.
The long outer perimeter of the walls was held by Simon, the central
part of the city by John, and the Temple by Eleazar. John and Simon
could rely on numbers and equipment, Eleazar on his strategic
position. But it was upon each other that they turned the weapons of
battle, ambush and fire, and great stocks of corn went up in flames.
Then John sent off a party of men, ostensibly to offer sacrifice but
in reality to cut Eleazar and his followers to pieces, thus gaining
possession of the Temple. Hence-forward, therefore, Jerusalem was
divided between two factions, until, on the approach of the Romans,
fighting the foreigner healed the breach between them.