VMS Help CMS, SHOW, HISTORY, Qualifiers, /BEFORE=date-time  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Lists all history information prior to a specified date. By
    default, the time is the current date and time. The time value
    can be an absolute, delta, or combination time value, or one of
    the following keywords: TODAY, TOMORROW, or YESTERDAY.