La clausola rebus sic stantibus nella giurisprudenza romana ed in alcuni ordinamenti europei moderni [Roman Law and the Institution of Change of Circumstances in Modern European Law ]

Change of circumstancies is an important institution in modern contract law. In Roman law, this institution had not been constructed systematically, but the jurists took into consideration the distribution of risk of impossibility of performance of contracts caused by unforeseen events according to different types of contract, customs, bona fides, and unjust enrichment, and provided pluralistic remedies including renegotiation, partial remissions of debts and unilateral dissolution of contract. Based on Roman law, medieval jurists had formed an abstract theory of clause rebus sic stantibus. Since legal humanistic and liberal natural law schools jurists had to face the fight between this clause and the principle pacta sunt servanda. This explains why the clause rebus sic stantibus was not normally included in modern European Civil codes and it entered into them little by little by way of doctrines and cases. Only in recent times many European Civil codes have expressly regulated the change of circumstancies and this is the trend also of the European private law. Noneless the study of the remedies suggested by Roman law may be still useful for a precise application of this rule in different situations.