On the second hypothesis it would have a closer analogy to the testament made in the _comitia calata_, and may have been introduced only when Plebeians were admitted to political rights in this assembly. It is true that this is not a necessary conclusion, for the _patres_ gathered armed for war in the Campus long before the enrolment of the Plebs for military duties or their admission to political rights; but we may at least say that, when this enrolment and admission were effected, this form of testament could be used by the Plebeians. If we accept the traditional date for the Servian constitution, it was common to the two orders before the close of the monarchy. But there was a third type of will, one purely plebeian, which from the comparative simplicity of its form and the readiness with which it could be employed (since it did not depend either on chance or formal gatherings of the people) gradually came, in its subsequent developments, to replace all others, and became the prevailing Roman form of testament-making. This was the testament _per aes et libram_, one use of the _mancipatio_ or solemn transference of property “by the copper and the scales.” In the form in which it is known to us, it is a late development, for the sale of the property has entirely ceased to be a real, and has become a fictitious sale; the mancipation in fact has become a mere formality, and its employment is said to have been dependent on the condition that the testator “subita morte urguebatur”[107]—a condition which implies that the comitial testament could in ordinary cases be resorted to. But as the Plebs had originally no access to this form of will, the testament _per aes et libram_ must have been in use among them long before its recognition as a form valid for the whole community. It was then regarded as a mere formal application of the mancipation to a special emergency, and as supplementary to the comitial testament; until its superior utility came to be recognised, the sentiment in favour of a free disposition of property grew to be strong, and the Twelve Tables, which effected the triumph of plebeian over patrician forms of procedure, recognised it as the normal mode of testate disposition.