The notion of a quasi-contract can be traced to Roman law and is still a concept used in some modern legal systems.
Quasi contract laws have been deduced from the Latin statement "Nemo debet locupletari ex aliena iactura", which proclaims that no one should grow rich out of another person's loss.
[1] The form of action known as indebitatus assumpsit came to include various sub-forms known as the common money counts.
The most important of these for the later development of the law of quasi-contract included: (i) actions for money had and received to the plaintiff's use; (ii) actions for money paid to the defendant's use; (iii) quantum meruit; and (iv) quantum valebant.
[2] Quasi-contractual actions were generally (but not exclusively) used to remedy what would now be called unjust enrichment.