The aqueduct riot
Flavius Josephus, The Jewish War 2.175-177
On a later occasion he provoked a fresh uproar by expending upon the construction of an aqueduct the sacred treasure known as Corbonas; the water was brought from a distance of seventy kilometers. Indignant at this proceeding, the populace formed a ring round the tribunal of Pilate, then on a visit to Jerusalem, and besieged him with angry clamor.
He, foreseeing the tumult, had interspersed among the crowd a troop of his soldiers, armed but disguised in civilian dress, with orders not to use their swords, but to beat any rioters with cudgels. He now from his tribunal gave the agreed signal.
Large numbers of the Jews perished, some from the blows which they received, others trodden to death by their companions in the ensuing flight. Cowed by the fate of the victims, the multitude was reduced to silence.
Flavius Josephus, Jewish Antiquities 18.60-62
He spent money from the sacred treasury in the construction of an aqueduct to bring water into Jerusalem, intercepting the source of the stream at a distance of thirty-five kilometers. The Jews did not acquiesce in the operations that this involved; and tens of thousands of men assembled and cried out against him, bidding him relinquish his promotion of such designs. Some too even hurled insults and abuse of the sort that a throng will commonly engage in.
He thereupon ordered a large number of soldiers to be dressed in Jewish garments, under which they carried clubs, and he sent them off this way and that, thus surrounding the Jews, whom he ordered to withdraw. When the Jews were in full torrent of abuse he gave his soldiers the prearranged signal.
They, however, inflicted much harder blows than Pilate had ordered, punishing alike both those who were rioting and those who were not. But the Jews showed no faint-heartedness; and so, caught unarmed, as they were, by men delivering a prepared attack, many of them actually were slain on the spot, while some withdrew disabled by blows. Thus ended the uprising.
NB: The Suda is a Byzantine dictionary from the tenth century, which uses older sources.
Korbanas: among the Jews the holy treasury. Pilate spent the holy treasury on an aqueduct and stirred up a riot. It brought in water from a distance of seventy-two kilometers. Bringing in his army, he killed many.
The construction of the aqueduct - its length was twenty kilometers - had been ordered by king Herod the Great. Pilate could not finish the building; it was inaugurated by king Herod Agrippa, who reigned in Jerusalem from 41 tot 44.
The treasury Flavius Josephus describes as Corbonas is known from Jewish sources as Qorban, and Jewish law permitted the use of money from this treasures for social welfare and public works.note[Mishna Šeqalim 4.2.] Of course the Temple authorities, whose duty it was to administer the money, had to cooperate, but their consent is implied in the story. Had they refused, Flavius Josephus would have told us that Pilate stole the money. It is unclear what Pilate did wrong, especially since the construction of an aqueduct was surely an undertaking that would have improved the inhabitants' standard of living enormously. Maybe his mistake was that he took the initiative, instead of allowing Caiaphas to take the credits?
The demonstration seems to have taken place at a feast, because Pilate was staying in Jerusalem. It may have been during this festival that the Roman soldiers "mingled the blood of the Galileans with their sacrifices".note[Luke 13.1.] The fact that Pilate's soldiers could be hidden among the populace, suggests that they were not Italians, but belonged to a locally recruited, Samarian unit (Ala I Sebastenorum or Cohors I Sebastenorum).