Elder Days

Elder Days was a term that, during the Second and Third Age, properly referred to the times before the end of the First Age. In that context, the Middle Days were the Second and Third Ages, whereas the Younger Days were the foreseen Dominion of Men.
However, in the Fourth Age the term began to be applied to all previous Ages, as the time before the Dominion of Men and the dwindling of the Elves and other races. Aragorn for instance, referred to himself as the last King of the Elder Days, according to the latter sense.