A more thorough explanation:

Definition: Testamentum is a Latin term used in Roman law to refer to a will.

In early and classical law, the mancipatory will was the standard form of will. However, in A.D. 446, the Western Empire accepted the holographic will. A will could also be made by registration on the court acta.

There were different types of testamentum in Roman law:

• Testamentum calatis comitiis: A will made before the comitia curiata, having an effect comparable to adrogation.
• Testamentum holografum: A will entirely written, dated, and signed by the testator in his own handwriting.
• Testamentum in procinctu: A will made by a soldier before a fellow soldier while preparing for battle.
• Testamentum militum: A will made by a soldier in active military service.
• Testamentum tripertitum: A will made without interruption, with seven witnesses to seal it, and signed by the testator.

For example, a testamentum holografum was a will entirely written, dated, and signed by the testator in his own handwriting. This type of will was accepted in the Western Empire in A.D. 446.

Another example is the testamentum in procinctu, which was a will made by a soldier before a fellow soldier while preparing for battle. This type of will was common in ancient Rome, where soldiers would make a will before going to war to ensure their property was distributed according to their wishes in case they did not return.