Some samples and a notebook sufficed them for their most important operations. They corresponded with each other on the strength of engagements which their interest obliged them to respect, in view of the enemies of every sort by whom they were surrounded. Commerce has lost the trace of the ingenious inventions which were the result of their efforts; but it is to their influence that it owes the rapid progress of which history shows us the brilliant phenomenon in the midst of the horrors of feudal darkness. Insensibly, the Jews were absorbing all the money, since this was the kind of property which they could acquire and keep safely.... For more than five hundred years, it is in the history of that nation that we must study the progress of commerce and the more or less venturesome attempts through which it has risen to the rank of political power.... The Jews were the depositaries of the finest cloths known, and they traded in them at immense profits: they extended the use and at the same time the demand for them into castles and into abbeys. They also engrossed the trade in jewelry and in gold and silver bullion. Feudalism disturbed these lucrative occupations less than one might suppose: the lords put upon them strict conditions, but they had the good sense to treat them with respect. Besides in the midst of the general terror which continually hovered around all highways and all travelers, the Jews, armed with safe-conducts, traveled all over Europe without inquietude, and in the tenth and eleventh centuries disposed like sovereigns of all the commerce of France. At that period, they had already greatly simplified commercial proceedings, and their correspondence would have done honor to the most able merchants of our great cities.