In the midst of a busy life I'm slowly rereading Tolkien's Lord of the Rings. Once again I'm slowly marching my way to Mount Doom with Frodo and Sam, hoping in darkness that a way may be found. I nearly know the books by heart, but it is always a joy to come back to them.
There are many reasons for LOTR success, but one of them is the incredible richness of the world. Tolkien has thought out how the world works, where it is located, what matters, and the whole damn history of the place. When a character references some random event, that event is fully formed in Tolkien's mind. He knows how it all fits together. Out of this richness comes this them of mourning. The world as known by the Elves is irreversibly changing. The way it was, it no longer can be. If the one ring is destroyed, then the power of the elvish rings will diminish, and the elves will fade away, only found in the deep woods. There is sadness attached to this fate. Yes, the ring must be destroyed, but much will be lost. The elves, as immortal creatures uniquely feel this loss, because isn't ancient history, but still a living memory.
It is history as mourning. Not so much because the past was better (in fact it was often worst) but because what was can never be again. Tolkien was speaking at the edge of history. His childhood world was no more and could not be recaptured or re-imagined. He grew up without cars or airplanes or modern communication. These technologies have brought many benefits to humanity, but as Tolkien recognizes they wrought much change. In the modern world communities and communal practices fade away. Relationships that defined a person, become inconveniences that are only dealt with at holidays. In the modern world languages fade into silence, cultures are overcome, and distinctions are blended.
The past wasn't perfect. It was full of pain and hurt, much like the present. But for good and for ill, what it represented is no more.