In order to rank as a noble in mediæval society it was, in general, necessary to be the holder of land for which only such services were due as were considered honorable, and none of those which it was customary for the peasant or serf to perform. The noble must, moreover, be a free man and have at least sufficient income to maintain himself and his horse without any sort of labor. The nobles enjoyed certain privileges which set them off from the non-noble classes. Many of these privileges were perpetuated in France, and elsewhere on the continent, down to the time of the French Revolution, and in Italy and Germany, into the nineteenth century. The most conspicuous privilege was a partial exemption from taxation. [Sidenote: Difficulty of classifying the nobles.] It is natural to wish to classify the nobility and to ask just what was the difference, for example, between a duke, a count, and a marquis. Unfortunately there was no fixed classification, at least before the thirteenth century. A count, for instance, might be a very inconspicuous person, having a fief no larger than the county of Charlemagne's time, or he might possess a great many of the older counties and rank in power with a duke. In general, however, it may be said that the dukes, counts, bishops, and abbots who held directly from the king were of the highest rank. Next to them came an intermediate class of nobles of the second order, generally subvassals of the king, and below these the simple knights. [Sidenote: Feudal registers.] 43. The great complexity of the feudal system of land tenure made it necessary for the feudal lords to keep careful registers of their possessions. Very few of these registers have been preserved, but we are so fortunate as to have one of the count of Champagne, dating from the early thirteenth century. This gives us an idea of what feudalism really was in practice, and shows how impossible it is to make a satisfactory map of any country during the feudal period. [Illustration: Fiefs and Suzerains of the Counts of Champagne] [Sidenote: Growth of the possessions of the counts of Champagne typical of the period.]