juries specially summoned for that purpose by the sheriff of the county, and they were obliged to find sureties that they would faithfully perform their important functions. Only in their presence could loans be validly contracted between Jews and Christians; and it was their duty to see the terms of all such bargains reduced to writing in a regular prescribed form in duplicate copies. No contract was binding unless a written copy or chirograph had been preserved in one or other of those repositories or arks, which thus served every purpose of a modern register, and other purposes as well. If the money-lender suffered violence and was robbed of his copy of the bond, the debtor was still held to his obligations by the duplicate which remained. If the Jew and all his relatives were slain, even then the debtor did not escape, but was confronted by a new and more powerful creditor, the king himself, armed with the chirograph. Lists of all transactions were preserved, and all acquittances and assignments of debts, known from their Hebrew name as “starrs,” had also to be carefully enrolled.[450] Minute and stringent rules, codified by Hubert Walter in the terms of a written commission, were issued to the judges when starting on their circuit in September, 1194.[451] Footnote 450: Cf. J. M. Rigg, _Sel. Pleas of the Jewish Exchequer_, p. xix. ----- Footnote 451: See chapter 24 of the _Forma procedendi in placitis coronae regis_, cited in _Sel. Charters_, 262. ----- If this cunningly-devised system prevented the Christian debtor from evading his obligations, it also placed the Jewish creditor completely at the mercy of the Crown; for the exact wealth of every Jew could be accurately ascertained from a scrutiny of the contents of the _archae_. The king’s officials were enabled to judge to a penny how much it was possible to wring from the coffers of the Jews, whose bonds, moreover, could be conveniently attached until they paid the tallage demanded. The custom of fixing on royal castles as the places for keeping these arks, probably explains the origin of the special jurisdiction exercised over the Jews by the king’s constables (“_qui turres nostras custodierunt_”).[452] In the dungeons of their strongholds horrible engines were at hand for enforcing obedience to their awards. Such jurisdiction, however, extended legitimately over trivial debts only.[453] All important pleas were reserved for the officials of the exchequer of the Jews, a special government department, which controlled and regulated the whole procedure. Evidences of the existence of this separate exchequer have been traced back to 1198, although no record has been found of a date prior to 1218.[454] John, while despising the Jews, was not slow to realize that in them the Crown possessed an asset of great value. It was his policy to protect their wealth as a reservoir from which he might draw in time of need, contenting himself meanwhile with comparatively moderate sums.