1. The typology of condictiones: classical or post-classical?

What were the other "condictiones"? The Digest contains separate titles for the condictio causa data causa non secuta (D. 12, 4), the condictio ob turpem vel iniustam causam (D.

12, 5), the condictio sine causa (D. 12, 7) and the condictio furtiva (D. 13, I);^[4313] the condictio indebiti is dealt with in D. 12, 6, the longest and most substantial title of them all.^[4314] To what extent these categories of enrichment liability were shaped by the classical Roman lawyers, by post-classical jurisprudence or by Tribonian, is not entirely clear. It is obvious that the classical jurists already attempted to carve out certain typical situations in which they were prepared to grant the condictio. Yet, for them the condictio was still a uniform procedural institution, without specifically differentiated requirements. Thus it would be wrong to insist on the classicity of the condictiones indebiti, ex causa furtiva, etc. as such—that is, as separate legal institutions. Classical law, strictly speaking, did not recognize specific types of condictiones, but applied the condictio to a number of situations in which it was thought to be unfair to leave the plaintiff without redress. It was only in post-classical times, when the formulae fell away and the classical concept of an "actional law" ultimately broke down, that the term "condictio" in its original procedural sense was no longer meaningful. In vulgar law, it disappeared completely,^{[4315] [4316] [4317] [4318]} and when Justinian revived it in his usual classicist spirit, its meaning had shifted: "condictio" had come to be a term of substantive law, and it was used to designate all those non­contractual and non-delictual claims, which the classical lawyers had been prepared to enforce by means of a condictio (in the old sense of the word). These claims were taken over, further developed, refined and systematized^[4319] by the East-Roman school of jurists, and it is in this form that they were ultimately received into the Corpus Juris Civilis. All in all, they constitute "one of [the] most distinctive and important achievements [of Roman jurisprudence]",^[4320] which has had a lasting impact on modern civilian systems.

We shall now deal with each of these "condictiones" (in the Justinianic sense) in turn.

More on the topic 1. The typology of condictiones: classical or post-classical?:

1. Classical and post-classical compromissum
2. Post-classical compilations of ius
3. The post-classical era
4. Changes in post-classical law
5. Post-classical jurists and law-schools
6. The post-classical period
7. 10 POST-CLASSICAL LAW AND PROCEDURE
8. The influence of Christianity on post-classical law
9. The Post-Classical Period of Roman Law
10. The Post-classical Period (Late Empire or Dominate)
11. Post-classical developments, Corpus Juris and ius commune
12. IV THE LITERATURE OF THE CLASSICAL AGE: ITS FORMS AND ITS TRANSMISSION
13. The end of classical jurisprudence
14. Classical Roman law
15. The classical period
16. The atrophy of the classical stipulation
17. THE CULMINATION OF CLASSICAL JURISPRUDENCE
18. THE JURISTS IN THE CLASSICAL PERIOD