This paper examines how seigneurial courts dispensed judgments and imposed punishments in western and central France in the eleventh and twelfth centuries, precisely the period during which the courts were being formed. The paper attempts to demonstrate that behind the apparent arbitrariness and frequent abuses of seigneurial justice were hidden a certain logic and rules. First, one aspect of seigneurial justice, its linkage with some contemporary practices of warfare, is noted. The ban seigneur would sometimes capture dependants who were suspected criminals and imprison them in his castle. He would release them only after they had redeemed themselves by paying fines. This practice had much in common with the hostage taking which was becoming increasingly common at almost the same period among knights fighting in war. Next, the usage and meanings of the word vicaria, which is thought to designate seigneurial rights to exercise justice, are examined. It has been discovered that the word signified the whole of seigneurial rights to exercise justice, but was often employed in a manner emphasizing the capture and detention of criminals and, above all, the fines imposed upon them. It can be understood, therefore, that the quasi-hostage-taking by ban seigneurs, noted above, is an extreme version of vicaria. Third, this paper proceeds to question how crimes were perceived as such and why fines, not corporal punishments, were almost exclusively imposed in this age. In answer to the first question, it is clear that people were not concerned with how and why crimes were committed, but instead where and when they were committed or discovered, and who should judge and punish them. In short, time and space were not homogeneous, and in order to determine in advance who was to be accused and what punishment would be imposed as a matter of course, time and space had been segmented and cut out beforehand. The answer to the second question is related to that to the first. This type of partitioning of time and space was not limited to the exercise of justice but extended to other seigneurial rights as well, such as military requisition, tolls, obligatory usage of the mill, the grape presser or the bread-caking stove, and so on. For this reason, fines were almost the only punishment imposed, and fines were understood as if they were the imposition of service or a tax. Finally, the paper examines how trials were carried out in the seigneurial courts. The analysis of historical sources show that ordeals, duels and purgatory oaths were very often employed and, most importantly, judges resorted to these measures from a strategic point of view.