Around the year 1000 most western European towns were small: a bishop's seat, a market, a few thousand people at most. Over the next three centuries trade grew so fast that historians speak of a commercial revolution. By 1300 Paris, Florence, Venice and Milan each probably held 100,000 people or more.

Town air

Towns were islands of a different kind of life. Townspeople, or burghers, bought or fought for charters from kings and lords granting them the right to run their own markets, courts and taxes. In many places a serf who lived in a chartered town for a year and a day could gain freedom from serfdom. German historians later summed this up in the saying "town air makes free".

In northern Italy towns became self-governing communes, city-states that ruled the surrounding countryside and elected their own officials. Flemish cities such as Bruges and Ghent grew rich weaving English wool into cloth, and the fairs of Champagne brought Italian and Flemish merchants together. In the north, the Hanseatic League, a network of north German trading towns led by Lubeck, dominated trade across the Baltic and North Sea. New business tools spread from Italy: partnerships, bills of exchange, double-entry bookkeeping and gold coins such as the Florentine florin, first struck in 1252. Towns were also loud, crowded and dirty, with frequent fires and high death rates, so they grew mainly by drawing migrants from the countryside.

Guilds

Townspeople organized themselves into guilds. Merchant guilds controlled trade; craft guilds grouped bakers, weavers, goldsmiths and dozens of other trades. Guilds set standards of quality, fixed hours and prices, looked after sick members and paid for funerals and feast-day processions. A young person entered a trade as an apprentice, living with a master for years, then became a journeyman paid by the day, and might hope to become a master. The masterpiece was originally the piece of work a journeyman submitted to prove he deserved to become a master.

Guilds protected their members by keeping others out. They limited competition, shut out newcomers and often closed their doors to women, Jews and the poor, though some trades, such as silk spinning in Paris, were run largely by women. Jews, barred from most guilds and in many places from owning land, were pushed toward moneylending, which the church forbade Christians to practice, and were then resented for it. England expelled its Jews in 1290, under Edward I, and France did the same in 1306.

Universities

The schools that grew up around cathedrals in the 1000s and 1100s gave birth to a new institution, and its name came from the language of guilds: universitas originally meant a corporation or guild, here a guild of teachers or students. At Bologna, famous for law, the students themselves formed the guild and hired, fined and fired their teachers. At Paris, famous for theology, the masters ran the university. Oxford, Cambridge, Salamanca, Padua and dozens more followed.

Students began with the liberal arts, especially logic, and could go on to law, medicine or theology. Degrees were licenses to teach. Teaching worked by lecture and by disputation, in which a question was argued on both sides. Peter Abelard's book Sic et Non (Yes and No) set conflicting statements from Christian authorities side by side and challenged readers to reconcile them. The arrival of Aristotle's works in Latin, many by way of Arabic, gave scholars a new toolkit, and Thomas Aquinas built a grand synthesis of Aristotle and Christian theology in the 1200s.

Towns also raised the great Gothic cathedrals, paid for by bishops, merchants and guilds alike. Gothic architecture is usually traced to Abbot Suger's rebuilding of the abbey church of Saint-Denis near Paris in the 1140s, with its pointed arches, ribbed vaults and walls of colored glass. Within a century, cities from Chartres to Cologne competed to build the tallest and brightest.

Worked example: a student writes home

Teachers of letter writing in medieval universities circulated model letters, and one of the most common types was the student asking for money. A typical example runs like this: the son greets his beloved parents, reports that he is studying hard in the city, explains that books are dear, lodgings costly and winter coming, and begs them to send money by the bearer so that he may finish what he has begun. Model replies survive too, including fathers scolding sons for idleness and extravagance.

The letter connects the ideas of this level. The student lives in a town with an expensive cash economy. He belongs to a university, a guild with its own privileges, including the right to be tried in church courts rather than by townsmen, which often led to brawls between "town and gown". He studies to earn a license that will give him a career as a clergyman, lawyer or teacher. The American historian Charles Homer Haskins collected such letters around 1900, and they show that some features of student life have barely changed.