The Renaissance originated in Italy for several reasons. The most fundamental reason was that Italy in the later Middle Ages was the most advanced urban society in all of Europe. Unlike aristocrats north of the Alps, Italian aristocrats customarily lived in urban centres rather than in rural castles and consequently became fully involved in urban public affairs. Moreover, since the Italian aristocracy built its palaces in the cities, the aristocratic class was less sharply set off from the class of rich merchants than in other European countries. Hence, whereas in France or Germany most aristocrats lived on the income from their lands while rich town dwellers, called bourgeois in French, gained their living from trade, in Italy so many town-dwelling aristocrats engaged in banking or mercantile enterprises, and so many rich mercantile families imitated the manners of the aristocracy that, by the fourteenth and fifteenth centuries, the aristocracy and upper bourgeoisie were becoming virtually indistinguishable. For instance, the noted Florentine family of the Medici, which had emerged as a family of physicians (as the name suggests), made its fortune in banking and commerce, and rose into the aristocracy in the fifteenth century. Obviously, social mobility as such brought about a great demand for education in the skills of reading and counting necessary to become a successful merchant, but the richest and most prominent families sought above all to find teachers who would impart to their sons the knowledge and skills necessary in politics and public life.