He made a specialty of
money lending for the purpose of building
abbeys and
monasteries. Among those built were the
Abbey of St Albans,
Lincoln Minster,
Peterborough Abbey, and no fewer than nine
Cistercian abbeys. They were all founded between 1140 and 1152, and at Aaron's death remained indebted to him in no less a sum than 6,400
marks. Some of these debts may, however, have been incurred by the abbeys to acquire lands pledged to Aaron. Thus the abbot of
Meaux took over from Aaron lands pledged to the latter in the sum of 1,800 marks; Aaron at the same time promising to commute the debt for a new one of only 1,260 marks, which was paid off by the abbey. After Aaron's death the original deed for 1,800 marks was brought to light, and the king's treasury demanded from the abbey the missing 540 marks. This incident indicates how, on the one hand, Aaron's activity enabled the abbeys to get possession of the lands belonging to the smaller barons, and, on the other, how his death brought the abbeys into the king's power. Aaron not only advanced money on land, but also on corn, armour and houses, and in this way acquired an interest in properties scattered through the eastern and southern counties of England. Upon his death Henry II seized his property as the
escheat of a
Jewish
usurer, and the English crown thus became universal heir to his estate. The actual cash treasure accumulated by Aaron was sent over to France to assist Henry in his war with
Philip Augustus, but the vessel containing it went down on the voyage between
Shoreham and
Dieppe. However, the indebtedness of the smaller barons and knights remained, and fell into the hands of the king to the amount of £15,000, owed by some 430 persons distributed over the English counties. His business operations were of an unprecedented scale, with his capital financing many of the great architectural projects of the Angevin period, including cathedrals and abbeys. So large was the amount that a separate division of the
exchequer was constituted, entitled "'''Aaron's Exchequer'
" (Madox, History of the Exchequer,'' folio ed., p. 745), and was continued till at least 1201, that is, fifteen years after his death, for on the pipe-roll of that year most of the debts to Aaron (about £7,500) are recorded as still outstanding to the king, showing that only half the debts had been paid over by that time, though, on the death of Aaron, the payment of interest ceased automatically, since the king, as a Christian, could not accept usury. == Massacre of Jews at York==