Abstract
The presentation shall deal with the attitudes of Roman lawyers towards fungibility, namely how they determined whether a thing is fungible or not. This might be done according to the objective approach given the inherent properties of things or by the subjective approach when the parties to the contract determine the fungibility of things subject to the contract.
To determine which approach was used by, or at least prevalent among, Roman jurists, multiple texts from Digest as well as Institutes of Gaius shall be analysed. Firstly, a short introduction based on Gaius Commentarius III, 90 mentioning "res pondere, numero, mensura constant" shall be given.
Then D 35, 2, 30, 2-5 and D 30, 30pr., which might also refer to "pondere, numero, mensura", shall be discussed as they might contain a subjective approach to fungibles. It is therefore necessary to determine whether this is really the case.
Afterwards, we shall turn to D 19, 2, 31 which does not contain the term "pondere, numero, mensura" but contains examples of such things together with the word "tantundem", to see whether it could enhance our perspective of fungibility in Roman law. Finally, a short conclusion on which approach Romans applied to fungibles shall be given.