Medieval Europe came of age in the twelfth century as also, it will be argued, did the Christian church. Growth, development, expansion, maturation and even affluence are all relative. Accepting that as a premise, we can still say that the twelfth century experienced all of these in a marked way. More and more land came under cultivation as woods were levelled, marshland filled and marginal lands made arable. No one knows for certain whether the growth in population created the need for more food supply or whether the increased food supply contributed to population growth. When farmers could grow more than subsistence required, the possibility of commerce was opened up. Selling the excess to towns, which were growing in number and size, provided the seller with actual money with which he could buy town-made goods, such as finished cloth. Commerce was the essential ingredient in defining a town, and commercial towns soon developed a merchant class and an artisan class, both of which organized themselves into guilds, which had a religious flavour. This rural-urban commercial nexus was the case particularly north of the Alps. Not just London, Paris and Cologne, but places like Worms, Bristol, Tours, Angers and dozens of other towns developed as places of robust commerce. Most importantly, the great towns of Flanders—Bruges, Ghent, Ypres, Lille and Arras—became centres of an international trade in textiles. The fields of England and Wales, many of them until recently woods, were now dotted with sheep, owing in large part to the work of the Cistercian monks (whom we shall soon meet more fully) as England became the largest wool producer in Europe and the principal supplier to the looms of Flanders. South of the Alps the story was somewhat different. There maritime cities developed thanks to an expanded commerce with the East. The crusades had opened up sea lanes, and luxury items (e.g., silks, spices) were imported. Ports such as Genoa, Pisa and, above all, Venice thrived on this trade. A vast market in international trade was held in the French province of Champagne, where fairs attracted merchants from much of Western Europe, who came there to deal in a wide variety of goods. Tin from England, cloth from Flanders, horses from Lombardy, spices from Syria via Italy, furs from Scandinavia and much else were bought and sold at what was Europe’s greatest wholesale market.