The next century saw the birth of another institution, the Council of Jurors, and there can be no doubt that it was to the Merchants' Guild that the Jury owed its origin.

With the increase of the population, outcome of the commercial development which signalised the opening of the twelve hundreds, the old machinery no longer sufficed for the maintenance of public peace and the regulation of trade. It became necessary to devise some new means to check the growing disorder, and the burghers, united as they were in the powerful organisation of their guild, were strong enough to take the matter into their own hands. Hence the Council of Jurors, a subsidiary body, annually elected by the people for policing the city and the management of municipal affairs, and which also participated with the College of Aldermen in the administration of justice.

So far from offering opposition, the sovereigns of Brabant from the first showed themselves favourable to this development. Not that they had any particular liking for democratic institutions, but because they were sufficiently clear-sighted to see that, in the interest of their revenue, it was incumbent on them to do so: they were well aware that the towns of Brabant depended wholly on trade, and that this delicate plant can only thrive in an atmosphere of freedom.

There is no record of the Jury at Brussels prior to 1229, at Antwerp till 1232, at Louvain till 1234, and at Tirlemont till 1249, but it is most likely that in all of these towns it dates from an earlier period, and by the close of the first half of the century it had been granted to almost all the communes of Brabant.

Its existence, however, as a body distinct from the higher magistracy was nowhere, save at Louvain, of long duration. As early as 1274 the Jury had disappeared at Brussels, and in hardly any of the great towns did it outlive the century. From the first the relations between the two corporations had almost everywhere been strained: they were the embodiment of hostile ideals—oligarchy and popular rule. Presently the burghers obtained a voice in the election of aldermen, and their term of office was limited to one year. The Council of Jurors thus ceased to be the sole expression of the will of the people; the higher magistracy had become, not only in theory, as it had always been, but in fact, representative of the city, and had risen proportionately in public esteem. Thus protected by the mantle of popularity, it was able, seemingly without opposition, little by little to itself assume the functions of its rival, and thus, little by little, to absorb it into its own bosom.

At Louvain, however, the case was different. In that city the aristocratic element was all-powerful, and the jury was recruited from the same families which furnished the College of Aldermen; from the first the two corporations had worked together in harmony, and until the end of the Middle Age they continued to exist as two distinct bodies.

For a long period after the municipal organisation of the cities of Brabant had been definitely determined, all administrative and legislative power remained in the hands of a narrow oligarchy of great capitalists, headed by the old patrician families, which from time immemorial had furnished the magistracy.

One was the source of their title to distinction—the ownership of land; but the means by which the first patricians had acquired their title-deeds were not in every case the same, nor were they all of like origin. Some of them were the descendants of ministeriales who, when the township was a feudal domain, had levied their lords' dues for him, and generally managed his affairs; others of yeomen of the same period, whom thrift or good fortune had enabled to purchase the freehold of the soil they tilled; others, again, were successful traders, or the sons of successful traders, who, retiring from business, had invested the wealth which commerce had given them in real property.

Together they formed a class apart, distinct alike from the feudal nobility and from the general body of townsmen. They were divided into groups in each city, which bore the characteristic title of lignages or clans; but it is certain that many patricians were not the direct lineal descendants of the houses whose names and arms they bore: the status of patrician was transmissible in the female line, and patrician daughters were not unfrequently given in marriage to prosperous plebeians; moreover, some of the sons of the house were only sons by adoption—the wealthy merchant of alien blood was not always refused admission to the charmed circle, though as a rule the door of matrimony was the only door open to him; and occasionally we find whole families, sometimes sections of families, forsaking their original clan to enroll themselves in another. Indeed, the great lignages of Brabant, which play so large a part in the stories of her towns, were, to a certain extent, voluntary associations of aristocratic families banded together for the sake of mutual protection and help, and with a view to securing the election of their own nominees to the magistracy; and though, no doubt, a considerable number of the members of each clan traced their descent to one stock, it is certain that the ties by which they were most strongly knit together were not those of blood, but of kindred pursuits, and kindred associations and kindred political interests. It is a significant fact, as Pirenne observes, that the number of lignages in each town corresponded to the number of their aldermen, and that each lignage had obtained a prescriptive right of representation in the magistracy.