De transactionibus axiomata

Nor, if he is sued for the performance of a promise, is he to be defended as having promised an undue thing, even if it later becomes evident that he owed nothing, provided the settlement was entered into in good faith.

CI.
In the last place, if a settlement has been made concerning some controversy, and if subsequently, because of a dispute reborn regarding the same business, an arbitration is agreed upon, it may not be irrelevant to ask whether it appears that one has retreated from the settlement by the arbitration, as if the newest pacts derogate from the prior ones. But because those entering into arbitration appear to be acting to preserve their rights, not to renounce them, they do not appear to have renounced the right acquired from the settlement, and therefore the settlement is not abolished by the arbitration.