ancient

adjective | an·cient

1. : existing from a long past date; specifically : having had an uninterrupted existence of 20 to 30 or more years : having had an uninterrupted existence of 20 to 30 or more years

   Note: Things and especially documents that are ancient benefit from a presumption that they are valid even though proof of their validity may be unavailable due to lapse of memory, absence of witnesses, or loss of documents.