These words are of frequent occurrence in the Roman writers and jurists, and have a great variety of siguifications, according to the matter to which they refer. Their general meaning is that of security given by one person to another, or security which one person obtains by the advice or assistance of another. The general term (cautio) is distributed into its species according to the particular kind of the security, which may be by satisdatio, by a fideiussio, and in various other ways. The general sense of the word cautio is accordingly modified by its adjuncts, as cautio fideiussoria, pigneraticia, or hypothecaria, and so on. Cautio is used to express both the security which a magistratus or a iudex may require one party to give to another, which applies to cases where there is a matter in dispute of which a court has already cognizance; and also the security which is a matter of contract between parties not in litigation. The words cautio and cavere are more particularly used in the latter sense.
If a thing is made a security from one person to another, the cautio becomes a matter of pignus or of hypotheca; if the cautio is the engagement of a surety on behalf of a principal, it is a cautio fideiussoria.
The cautio was most frequently a writing, which expressed the object of the parties to it; accordingly, the word cautio came to signify both the instrument (chirographum or instrumentum) and the object which it was the purpose of the instrument to secure. The phrase cavere aliquid alicui expressed the fact of one person giving security to another as to some particular thing or act. [p. 306]
Cautiones which were a branch of stipulationes were such contracts as would be ground of actions.
In many cases a heres could not safely pay legacies, unless the legatee gave security (cautio) to refund in case the will under which he claimed should turn out to be bad. The cautio Muciana was the engagement by which the heres bound himself to fulfil the conditions of his testator's will, or to give up the inheritance. The heres was also, in some cases, bound to give security for the payment of legacies, or the legatee was entitled to the bonorum possessio. Tutores and curatores were required to give security (satisdare) for the due administration of the property intrusted to them, unless the tutor was appointed by testament, or unless the curator was a curator legitimus. A procurator who sued in the name of an absent party might be required to give security that the absent party would consent to be concluded by the act of his procurator; this security was a species of satisdatio, included under the genus cautio. In the case of damnum infectum, the owner of the land or property threatened with the mischief might call for security on the person threatening the mischief.
If a vendor sold a thing, it was usual for him to declare that he had a good title to it, and that if any person recovered it from the purchaser by a better title, he would make it good to the purchaser; and in some cases the cautio was for double the value of the thing. This was, in fact, a warranty.
The word cautio was also applied to the release which a debtor obtained from his creditor on satisfying his demand; in this sense cautio is equivalent to a modern receipt; it is the debtor's security against the same demand being made a second time. Thus cavere ab aliquo signifies to obtain this kind of security. A person to whom the usus fructus of a thing was given might be required to give security that he would enjoy and use it properly, and not waste it.
Cavere is also applied to express the professional advice and assistance of a lawyer to his client for his conduct in any legal matter.
The word cavere and its derivatives are also used to express the provisions of a law by which anything is forbidden or ordered, as in the phrase Cautum est lege, etc. It is also used to express the words in a will by which a testator declares his wish that certain things should be done after his death. The preparation of the instruments of cautio was, of course, the business of a lawyer.
It is unnecessary to particularize further the species of cautio, as they belong to their several heads in the law.