Partly for this reason Sir Thomas Gresham had recently built the Royal Exchange, the most fabulous commercial building of its day. (Gresham is traditionally associated with Gresham's law--that bad money drives out good--which he may or may not actually have formulated.) Modeled on the Bourse in Antwerp, the Exchange contained 150 small shops, making it one of the world's first shopping malls, but its primary purpose and virtue was that for the first time it allowed City merchants--some four thousand of them--to conduct their business indoors out of the rain. We may marvel that they waited so long to escape the English weather, but there we are.