2.  Medieval contract law

greatest, of its members, Azo, and his pupil Accursius (who wrote in the early thirteenth century).

It is important to note that none of the glossators seems to have been familiar with the ethical writings of Aristotle, which had also been lost in the West and were not to be generally available again until their translation in to Latin in the mid-thirteenth century. This means that, while the glossators developed the doctrine of causa, teaching that the absence of causa did not simply give rise to a defence (the exceptio doli) as in classical Roman law, but meant that the contract was seen as invalid ex nunc,27 they did not put causa to the same Aristotelian uses as later scholars were to. Nonetheless, what the glossators did teach tended to the exclusion of undertakings given without any underlying causa or reason for the transaction.

The glossators’ great achievement was in discovering and enunciating general principles in the Digest, which, as was discussed earlier, was not one of the great strengths of the classical Roman law. Accursius, for instance, noted the passage at D. 2.14.1.3, stating that all contracts require consent, an observation which was clearly of use in developing the law’s later stress upon the idea of consent and agreement in contract. The glossators’­ interest in general principles bore fruit in a tendency to coin general maxims or brocards expressing legal rules, though it was not until the sixteenth century that the most important maxim, pacta sunt servanda, was to be coined by the canonist Hostiensis.28

The glossators were followed by the so-called ‘post-glossators’, or ‘commentators’, writing from the mid-thirteenth century onwards, of whom the two greatest were Bartolus de Saxoferrato (who died in 1357) and his pupil Baldus de Ubaldis (who died in 1400). These scholars had the benefit both of the Roman texts, as well as the ethical writings of Aristotle. Bartolus, for instance, knew that, under the Roman law, a stipulatio might be binding even if made gratuitously, but also that it required a causa. Bartolus therefore, applying an Aristotelian approach to the idea of causa, explained that causa must mean either the receipt of something in return for what was promised or the undertaking of the promise out of ­liberality.29 In similar Aristotelian vein, Baldus discussed when a contract might be presumed to have been made foolishly rather than out of liberality.30 He also used

27See further Zimmermann, Law of Obligations, p. 551.

28See earlier discussion in Ch. 2, at p. 82.

29Bartolus, Commentaria to D.44.4.2.3.

30Baldus, Commentaria to C. 4.30.13, no. 14.

his understanding of causa to explain the canonist rule that an informal executory agreement was binding. This was so, as long as the agreement had a causa (in the sense described by Baldus).31 This approach of the post-glossators was clearly in keeping with the view of Thomas Aquinas expressed in the previous century, but the significance for legal development lay in the fact that the post-glossators were first and foremost legal scholars rather than theologians with an interest in law.

The apogee of medieval legal scholarship is found, however, neither in the scholastic writings of the glossators nor of the post-glossators, but in that of the late scholastics, or Spanish natural law school. It was this school which combined most fully Roman law with Aristotelian ideas to produce a systematic theory of law, and one in which promise found a prominent place. The Spanish scholastics were heavily influenced by the Aristotelian-Thomist stress upon the virtues of promise-keeping, commutative justice and liberality,32 and used the concept of the promise to explain both the unilateral promise as well as the pact or agreement, the latter being a promise accepted by another and made either for reasons of commutative justice or liberality.33 They debated questions such as whether it was unjust to break a promise made for reasons of liberality if the promisee would merely be disappointed but not worse off as a result of the breach, Connanus (a French contemporary of the Spanish schoolmen) and Cajetan holding it was not, Lessius and Molina disagreeing.34 Lessius was concerned that Cajetan’s view would lead to the conclusion that merely executory contracts were not binding. The view of Molina, that the intention to undertake a gratuitous promise was sufficient to create a valid and binding obligation was to become especially influential in the enforcement in Scots law of unilateral gratuitous promises.35 Such debates were to continue in to the twentieth century, where, as discussed in the last chapter, reliance theorists would argue for a position similar to that advocated by Connanus and Cajetan.

Those scholastics who held that all promises were binding, regardless of the effect upon the promisee, had to answer the question of whether a promise had to be communicated and whether it had to be accepted before it was binding. Soto and Molina were of the view that, while the

31Baldus Commentaria to C. 3.36.15, no. 3.

32Gordley, ‘Philosophical Origins’, p. 71.

33See for instance Lessius, De iustitia et jure, 2.17.1; Molina, De iustitia et jure, disp. 252.

34See Cajetan, Commentaria to Summa Theologica, II-II, Q. 88, Art.1; Q. 113, Art. 1; Connanus, Commentariorum, 1.6.1; Lessius, De iustitia et iure, 2.18.2; Molina, De iustitia et iure, disp. 262.

35See later discussion of the views of Stair, at pp. 134ff.