From Yiddish באבע מעשה. Compares also to Slavic баба (grandmother). The roots of this expression lie in the Medieval Anglo-Norman chivalric romance, Sir Bevis of Hampton. When rewritten in Yiddish for Jewish audience by Elia Levita, and printed in 1541, it came to be known as Bove meise or Bovo-Bukh.
bubbe meise (plural bubbe meises)