1. The Origins and the Division thereof.
Obligationes
The Origins and the Division thereof.
José Luis Alonso & Jakub Urbanik The Roman Law of Obligation I Chair of Roman and Antique Law University of Warsaw

2. What is an Obligation?
G. 4.2 In personam actio est, qua agimus cum aliquo, qui nobis vel ex contractu vel ex delicto obligatus est, id est cum intendimus dare facere praestare oportere
A personal action is the one by which we sue the one, who has been obliged towards us either from a contract or from a delict, that is when we intend the he shall give, do, perform.
D pr. Paulus, 2. Inst.: Obligationum substantia non in eo consistit, ut aliquod corpus nostrum aut servitutem nostram faciat, sed ut alium nobis obstringat ad dandum aliquid vel faciendum vel praestandum.
The essence of obligations does not consist in that it makes some property or servitude ours, but that it binds another person to give, to do or to perform something for us.
I pr. Obligatio est iuris vinculum, quo necessitate adstringimur alicuius solvendae rei secundum nostrae civitatis iura.
Obligation is a legal tie, by which are necessarily bound to perform a certain thing according to the laws of our state.

3. The Genesis of an ‘Obligation’
The factors in the Archaic Times:
ILLICIT DEEDS (later: DELICTS/TORTS): TALION & agreements on damages/ obligation to compensate in the Law of XII Tables Table VIII 2. si membrum rup(s)it, ni cum eo pacit, talio esto. If one has maimed a limb and does not compromise with the injured person, let there be retaliation.
LICIT ACTS (later: PACTS, CONTRACTS:
NEXUM, FIDUCIA (transactions by scale and bronze) legis actio per manus iniectionem
vas (vades), praes (praedes),stipulatio

4. The Genesis contind. Schulds- und Haftungstheorie: Alois von Brinz
DUTY versus LIABILITY
Arguments in favour:
Legal anthropology/Comparative research: reine Sachhaftung
Traces in Roman Law? natural obligation, nexum, fiducia, vades & praedes

5. Sources of the Obligations
Illicit and Licit Deeds

6. Binomial division of the sources in the Institutions of Gaius
G. 3.88: Et nunc transeamus ad obligationes. Omnis enim obligatio vel ex contractu nascitur vel ex delicto.
And now we shall pass to obligations. Every obligation rises either from contract or from delict.

7. ‘Other figures’
D pr. Gaius 2 aureorum sive rerum cottidianarum: Obligationes aut ex contractu nascuntur aut ex maleficio aut proprio quodam iure ex variis causarum figuris
Gaius, 2 book of The Golden or Everyday Things: Obligations arise from either from contract or from wrongdoing or by some special right from various types of causes.

8. G. 3.89-91: the 3rd category found
First let us consider those that arise from contract. Of such there four kinds: for an obligation by contract arises either by a thing (re), by words (verbis), by letters (litteris), or by (simple) consent (consensu). A real obligation is contracted, for instance, by conveyance on loan for consumption. such a contract takes place properly in the case of things that are reckoned by weight, number, or measure – such things as money, wine, oil, corn, bronze, silver, gold (...). 91. he too who receives what is not due to him from one who pays in error comes under a real obligation. For the condictio with the pleading ‘if it appear that the defendant is bound to give’ lies against him precisely as if he had received the payment by way of loan (...) This sort of obligation, however, appears not to be founded on contract, because one who gives with intent to pay means to untie rather to tie a bound. (quia is qui solvendi animo dat, magis distrahere vult negotium quam contrahere).

9. The apparent contradiction in Gaius solved:
Different character of the books (Institutions: a scholarly manual, Golden Things: a handbook for practitioners)
Undue payment found in the Institutions

10. LABEO
D Ulpianus libro 11 ad Ed.: Labeo libro primo praetoris urbani definit, quod quaedam agantur, quaedam gerantur, quaedam contrahantur: et actum quidem generale verbum esse sive verbis, sive re quid agatur ut in stipulatione vel numeratione: contractum autem ultrocitroque obligatione, quod Graeci vocant, veluti emptionem venditionem, locationem conductionem, societatem: gestum rem significare sine verbis factam.
Labeo in the first book on the edict of urban praetor defines that some things are acted, other carried out, other contracted. And indeed ‘acted’ is a general word whether something is acted by words or things, like in stipulation or computation. ‘Contracted’ denotes bilateral obligation which the Greeks call synallagma, as for instance, sale or purchase, hire or partnership. ‘Carried out’ means a thing done without words.
sunãllagma

11. For further explanation see Introduction II
other divisions
unilateral / bilateral (simultaneous - consecutive)
stricti iuris bonae fidei
natural obligation
For further explanation see Introduction II

12. The Content of Obligation
impossibilium nulla obligatio est!
what is impossibility?

13. Marcus has made an agreement with a very decent widow Livia, that she should perform in his comedy. On the day of the performance however Livia does not appear in the theatre. Can he sue her?

14. the content of obligation
nemo alteri stipulari postest
Publius asked Aulus “Do you promise to pay my father 1000 denarii?” to which he answered “Yes, I do”. Is Aulus bound to pay?

15. the content of obligation
precisely defined content of performance
Definable in Money

16. the content of obligation
G. 4.2 In personam actio est, qua agimus cum aliquo, qui nobis vel ex contractu vel ex delicto obligatus est, id est cum intendimus dare facere praestare oportere
A personal action is the one by which we sue the one, who has been obliged towards us either from a contract or from a delict, that is when we intend the he shall give, do, perform.
DARE - FACERE - PRAESTARE
For further explanation see Introduction II
Divisibility - Indivisibility