A more thorough explanation:

Literae sigillatae is a Latin term that refers to sealed letters. In history, important documents were often sealed with a stamp or wax to ensure their authenticity and confidentiality. For example, a sheriff's return on a writ was often called literae sigillatae.

• A medieval king would often send literae sigillatae to his nobles to communicate important messages.
• During the Roman Empire, literae sigillatae were used to send official orders and decrees to different parts of the empire.

These examples illustrate how literae sigillatae were used in different historical contexts to ensure the security and validity of important documents.