[1] The concept of a testamentary document as similar to but distinct from a will originated in Roman law.
In the pre-classical period, a testator was required to nominate an heir in order for his will to be valid (heredis institutio).
[6] It is acknowledged that classical Roman inheritance law was "highly complicated and to a large extent perplexedly entangled" (Fritz Schulz).
[7] The codicil remained an entity distinct from a will (testament) to varying degrees throughout the Roman-influenced legal world.
The concept of heredis institutio was part of the jus commune until modern times.