That required money, and hitherto even princes had rarely been rich.

The increasing wealth of England, France, and Flanders at this time was based upon the wool industry and the manufacture and commerce to which it gave rise.

The Lord Chancellor in the House of Lords to this day sits on a woolsack, which is a reminder of the time when the woolsacks of England were the chief source of the wealth of English traders.
After the Black Death, an awful plague that swept through Europe in 1349, a large part of the land of England was given up to sheep grazing, because the population had diminished, and it took fewer people to look after sheep than it did to till the soil.

Although this had been an evil in the beginning, it became afterwards a benefit, for English wool was sold at an excellent price to the merchants of Flanders, who worked it up into cloth, and in their turn sold that all over Europe with big profits.

The larger merchants who regulated the wool traffic were prosperous, and so too the landowners and princes whose property thus increased in value.