 The vestibule's alignment at right angles of private interior spaces, and the use of doors and curtains also added security and privacy from the outside.The Classical Period marked a change in the need for privacy in Greek society, which ultimately led to the design and use of vestibules in Greek homes.In ancient Roman architecture, where the term originates, a vestibule () was a space that was sometimes present between the interior "fauces" of a building leading to the atrium and the street.