dateless

(s) having no known beginning and presumably no end
- the dateless rise and fall of the tides
- time is endless
- sempiternal truth
sempiternal, endless,
(s) of such great duration as to preclude the possibility of being assigned a date
- dateless customs
(s) not bearing a date
- a dateless letter
undated,
(s) unaffected by time
- few characters are so dateless as Hamlet
- Helen's timeless beauty
timeless,

sempiternal endless undated timeless