TITLE XXIX. OF THE MODES IN WHICH OBLIGATIONS ARE DISCHARGED
An obligation is always extinguished by performance of what is owed, or by performance of something else with the creditor's assent. It is immaterial from whom the performance proceeds—be it the debtor himself, or some one else on his behalf: for on performance by a third person the debtor is released, whether he knows of it or not, and even when it is against his will. Performance by the debtor releases, besides himself, his sureties, and conversely performance by a surety releases, besides himself, the principal debtor.
1 Acceptilation is another mode of extinguishing an obligation, and is, in its nature, an acknowledgement of a fictitious performance. For instance, if something is due to Titius under a verbal contract, and he wishes to release it, it can be done by his allowing the debtor to ask 'that which I promised thee has thou received?' and by his replying 'I have received it.' An acceptilation can be made in Greek, provided the form corresponds to that of the Latin words, as 'exeis labon denaria tosa; exo labon.' This process, as we said, discharges only obligations which arise from verbal contract, and no others, for it seemed only natural that where words can bind words may also loose: but a debt due from any other cause may be transformed into a debt by stipulation, and then released by an imaginary verbal payment or acceptilation. So, too, as a debt can be lawfully discharged in part, so acceptilation may be made of part only.
2 A stipulation has been invented, commonly called Aquilian, by which an obligation of any kind whatsoever can be clothed in stipulation form, and then extinguished by acceptilation; for by this process any kind of obligation may be novated. Its terms, as settled by Gallus Aquilius, are as follow: 'Whatever, and on whatsoever ground, you are or shall be compellable to convey to or do for me, either now or on a future specified day, and for whatsoever I have or shall have against you an action personal or real, or any extraordinary remedy, and whatsoever of mine you hold or possess naturally or civilly, or would possess, or now fail to possess through some wilful fault of your own—as the value of each and all of these claims Aulua Agerius stipulated for the payment of such and such a sum, and payment was formally promised by Numerius Negidius.' Then conversely, Numerius Negidius asked Aulus Agerius, 'hast thou received the whole of what I have today engaged, by the Aquilian stipulation, to pay thee?' to which Aulus Agerius replied 'I have it, and account it received.'
3 Novation is another mode of extinguishing an obligation, and takes place when you owe Seius a sum, and he stipulates for payment thereof from Titius; for the intervention of a new person gives birth to a new obligation, and the first obligation is transformed into the second, and ceases to exist. Sometimes indeed the first stipulation is avoided by novation even though the second is of no effect: for instance, if you owe Titius a sum, and he stipulates for payment thereof from a pupil without his guardian's authority, he loses his claim altogether, for you, the original debtor, are discharged, and the second obligation is unenforceable. The same does not hold if one stipulate from a slave; for then the former debtor continues bound as fully as if one had stipulated from no one. But when the original debtor is the promisor, a second stipulation produces a novation only if it contains something new—if a condition, for instance, or a term, or a surety be added, or taken away—though, supposing the addition of a condition, we must be understood to mean that a novation is produced only if the condition is accomplished: if it fails, the prior obligation continues in force. Among the older lawyers it was an established rule, that a novation was effected only when it was with that intention that the parties entered into the second obligation; but as this still left it doubtful when the intention was present and when absent, various presumptions were established as to the matter by different persons in different cases. We therefore issued our constitution, enacting most clearly that no novation shall take place unless the contracting parties expressly state their intention to be the extinction of the prior obligation, and that in default of such statement, the first obligation shall subsist, and have the second also added to it: the result being two obligations resting each on its own independent ground, as is prescribed by the constitution, and as can be more fully ascertained by perusing the same.
4 Moreover, those obligations which are contracted by consent alone are dissolved by a contrary agreement. For instance, if Titius and Seius agree that the latter shall buy an estate at Tusculum for a hundred aurei, and then before execution on either side by payment of the price or delivery of the estate they arrange to abandon the sale, they are both released. The case is the same with hire and the other contracts which are formed by consent alone.