A more thorough explanation:

Definition: Infra praesidia (in-frə prə-sid-ee-ə). A historical international-law doctrine that states that if someone captures goods and brings them completely within their power, they will be considered the owner of the goods.

This term comes from the Latin term "intra praesidia," which referred to goods or persons taken by an enemy during war. Under the principle of postliminium, the captured person's rights or goods were restored to prewar status when the captured person returned.

Example: During a war, if an enemy captures a person or goods and brings them within their own lines, they are considered the owner of those goods. However, if the captured person or goods return during the same war, they have postliminium, and their rights are restored to them as if they had not been captured by the enemy.

This example illustrates how the doctrine of infra praesidia worked in practice during times of war. It shows that captured goods or persons were only considered lost if they were brought completely within the captor's power and did not return during the same war.