There has existed since ancient times the need, particularly in the area of commercial traffic, to be able to transfer a commitment to pay a debt to a third party. A singular succession of a debt, whilst maintaining the obliga-tion, whereby the liability is transferred to a succeeding debtor, was not considered possible under Justinian Law (Codex Justinianus) and in the Ius Commune. In these legal systems the obligation was considered to be a personal engagement between creditor and debtor, and a succeeding debtor could only bind himself on the basis of an independent obligation to the creditor. According to Justinian Law, the creation of an obligation for the succeeding debtor instead of the original debtor could be achieved if the succeeding debtor in a legal proceeding acted as procurator in rem suam for the original debtor. If the succeeding debtor in this procedure would enter into litis contestatio with the creditor, then, from that point on, the original debtor would be freed from his obligation, and any judgement would be issued against the succeeding debtor. Because the succeeding debtor had accepted the liability in his own interest (in rem suam), he could not recover from the debtor in the event of any required payment to the creditor. Although a debtor could only be freed from his obligation to a creditor, if that creditor and a succeeding debtor entered into litis contestatio; C. 2,3,2 shows that the debtor could plead a defense against the creditor if the latter had implied his agreement to the transfer of debt by bringing legal action against the succeeding debtor. In the second place, under Justinian Law, a succeeding debtor could be legally bound instead of the original debtor by novation. The original obligation would be discharged through novation, which meant that all accessory rights and defenses would also be cancelled. If parties wanted to call on these accessory rights and defenses after novation, then it would be necessary that they be re-established. Only in the event of already ...