Breach of Contract

As previously noted, when parties entered into a contractual relationship they created an obligation by which one party (the debtor) was obliged to perform in favour of the other (the creditor).

With regard to actions stemming from the ius strictum and directed at making a specific performance in the form of a particular object (certa res) or a certain sum of money (certa pecunia), the debtor was initially not held liable for impossibility of performance caused by his own fault and hence no damages could be sought in such a case. To remedy this unjust situation, the basic rule was in later times modified by the principle that an obligation remained in force if the impossibility of perfor­mance was the result of fault (dolus or culpa) on the part of the debtor.^[667] The debtor was then condemned to pay the creditor a sum of money equal to the cost for the creditor to have the duty performed. As a rule, that compensation included the actual loss the creditor suffered due to non-performance as well as the loss of profit.

With regard to actions arising from bona fides and directed at an indefinite object (incerta res), the debtor could be held liable if performance was not carried out due to his dolus or culpa.^[668] In the time of Justinian this principle prevailed in respect of all actions, irrespective of whether or not they originated in the ius strictum and whether or not they were directed at a specific object.

4.3.9.1     Mora

A special form of non-performance was mora: an unjustified delay on the part of a contracting party to discharge an obligation.

Mora debitoris occurred when performance was due and possible, but the debtor failed to perform due to his fault. Normally, this transpired when he wilfully (dolo malo) deferred or delayed discharging the performance.^[669] This invites us to consider the question of when performance was due. If the parties had agreed that performance was due before or on a certain day, the debtor fell into default without further notice if he failed to discharge his legal duty at the proper time. This form of default was referred to as mora ex re, since no request by the creditor was necessary.^[670] On the other hand, if no particular day for performance had been set the creditor first had to request the debtor to fulfil his duty (interpellatio) before there could be mora. Otherwise, the debtor would not know that the creditor wanted performance and thus there would be no fault on his part. In this case, the default was described as mora ex persona.

As regards the legal consequences of mora debitoris, attention must be drawn to the distinction between actions arising from ius strictum and those arising from bona fides. With respect to the former, the principle prevailed that the debtor who was in mora had to perform as long as performance could be carried out. If he performed, even though he was in default, his liability was extinguished. However, if performance became impossible after the debtor fell into default there was originally no liability on his part. To rectify this situation the principle was introduced that the debtor's mora perpetuated the obligation (mora debitoris perpetuat obligationem). This means that the obligation, even though impossible to perform, remained in force after the debtor was in mora and the creditor could sue for a sum of money equal to the value of the performance.

Mora debitoris dissolved when the attached obligation was extinguished or when the debtor rendered performance or offered to perform. If the creditor failed to accept the tender of performance by the debtor without a just cause (sine iusta causa), he himself fell into default.^[673] This introduces us to the second form of mora, namely mora creditoris.

Mora creditoris occurred when the creditor refused without a good reason to accept a properly tendered performance or when he made it impossible for the

debtor to discharge his obligation by, for instance, being absent. It should be noted that this form of mora arose not only when the failure to accept the performance was due to the creditor’s fault, but also where no fault could be attributed to him, for example if his absence was caused by illness or by other reasons beyond his control.^[674]

The main effect of the mora creditoris meant the debtor was now liable only for dolus, i.e. only in cases where he wilfully made performance impossible. In all other cases, the risk of loss or impossibility passed to the creditor.^[675] Furthermore, the debtor could claim compensation for damages suffered as a result of the mora creditoris (for instance he was entitled to reimbursement of storage or maintenance costs) and could employ the exceptio doli as a defence against any claim by the creditor for performance until his damage had been compensated.^[676] Mora creditoris ceased to exist when the creditor declared his intention to accept the performance.^[677]

4.4