Impossible Promises

A promise to do what could not be done was not binding impossibilium nulla obligatio est. A thing was impossible when it was something that no one could do, not merely something which the promisor could not do. The promise might be to do an act physically impossible as a promise to give something that does not or cannot exist, as a slave that has died, or a "hippocentaur" or legally impossible, as to give something which could not be privately owned, as a forum, theatre or burial place.

So if one agreed to buy what, unknown to him, was already his own, there was no contract, for what is a man's own cannot be given to him. But if a man agreed to give something which, although he did not own it, was yet in existence and capable of being given by the owner, for example, 100 pounds of copper, the contract was valid, for the impossibility existed only when none could perform the promise.

An impossible promise was not binding though neither party or both parties knew of the impossibility. But if a person knowingly made an impossible promise to a person ignorant of the impossibility, the promisor was liable to the promisee in an action of deceit for any loss sustained. And if the promisee knew of the impossibility but the promisor did not, the promisee was bound on his part.

Thus if the vendee of a house knew that at the time of the sale the house was burnt, but the vendor did not know, the sale was good and the vendee liable for the price1.

1 William Alexander Hunter. A Systematic and Historical Exposition of Roman Law in the Order of a Code. p.598.

.

Effects of Marriage with Manus

By the strict marriage the wife passed into the marital power of her husband {in manum viri). The manus or marital power may be regarded as a particular form of the patria potestas. An uxor in manu was a member of her husband's household. Although called a materfamilias, this term did not have a meaning corresponding to the term paterfamilias. The wife was not the head of the family. She stood legally in the position of a daughter {in loco filiafamilias) of her husband. If she had children she was regarded as a sister of her own children. The relation of husband and wife, both as regards the wife's person and her property, was governed by the same rules of law as governed the relation of father and child. The law of husband and wife may, therefore, be considered as merely a particular branch of the law of parent and child. The husband had, in general, the same power over the person of his wife in manu as the father had over his child. Anciently, it may be suppo...
Read more

Slavery by Birth

The children of a female slave became the slaves of her master. The status of the father as free or slave was immaterial. The general rule governing the determination of the status of a child, whether as free or slave, or as citizen or alien, was as follows : Children born in lawful wedlock had the status of the father at the moment of conception, children born out of wedlock had the status of the mother at the moment of birth. Hence if the father of a child of a lawful marriage was free at the moment of conception, the child was free although the father should subsequently lose his freedom. As to children born out of wedlock, the general rule, as above stated, was that it was the status of the mother at the moment of birth that determined the status of the child. If the mother was free at the moment of conception but a slave at the moment of birth, the child was a slave, and conversely. This was the earlier law, but the rule was modified in the interest of liber...
Read more

Mandate (Mandatum)

Mandate (mandatum) was a contract by which one person mandatarius agreed to do something gratuitously at the request of another mandator , who, on his part, agreed to save him harmless from all loss in so doing. The mandator was said to give the mandatory a mandate, or commission to do the act in question. The term mandatum is sometimes translated "agency", but this translation is misleading. The mandatory is not properly described as an agent. Mandate was the only gratuitous consensual contract; the others, sale, hiring, and partnership, all being founded upon a consideration. Like the others, it was a bona fidei negotium , and bound the parties to do all that was required by good faith. It was of the essence of the contract of mandate that the mandatory should act gratuitously. But while this was true in a strict legal sense, it was allowed to agree upon a sum to be paid as a honorium , or salary, which might be recovered only by a special action and not b...
Read more