The evolution of Anzac Day is a fascinating study in national identity.
In particular, it's intriguing how the sombre anniversary of a brutal military campaign has survived the generations that experienced it directly and morphed into a general commemoration of Australia's military tradition.
The first Anzac Days were marked while World War I was still raging and were, probably, a communal attempt to rationalise the extraordinary losses experienced on Gallipoli in 1915.
Australians had previously gone overseas to fight for the British Empire of which they were proudly part, but earlier conflicts had been relative skirmishes compared to the slaughter of Anzac.
Yet even as Australians digested the reality of this new kind of warfare and absorbed its impact on their homes and hearths, the bloodshed and killing went on unabated until 1918.
By the time the war was over, scarcely a family or township, no matter how small, had escaped without loss.
Small wonder the entire nation needed some shared ceremonies to help it cope.
Anzac Day, with its dawn services, odes, hymns and other traditions became the hinge of Australia's emotional response to a profound collective injury. The returned soldiers of the so-called “Great War” kept the flame of remembrance alive, with the help and support of many grieving families and communities.
When war came again in 1939, the heroic myths of Anzac were re-conjured, partly for the new purpose of inspiring courage in another generation.
A second great wave of returned service personnel reinforced the ranks of the first Anzacs after World War II, cementing Anzac Day as an occasion that transcended not only campaigns but entire conflicts and generations of Australians.
As decades passed and new, less “popular” wars flared and faded it seemed that Anzac Day might become obsolete.
Songs and plays explored the idea of “the one day of the year” when the emotions and pain of those wounded in war were permitted public expression.
To many, some aspects of this annual outpouring could appear frankly disreputable, fuelling the belief that soon, none would remain to join the marches.
But instead of fading away with the thinning ranks of veterans, Anzac Day has experienced a resurgence.
New generations, mostly untouched by war, are seeking connection with the traditions of their forebears, trying to comprehend the nature of the wound that left such a deep national scar.
In this quest, Anzac Day itself has undergone a transformation.
In the 21st century the day has taken on an even more sacred significance, with old observances overlaid by new ones, including pilgrimages by the young to altars of past sacrifice at Gallipoli, Kokoda and the Western Front.
The Anzac Day of 2013 is far removed from that of 1916.
Yet, for all that, its resurgence demonstrates that Australians have never lost sight of the time-honoured central exhortation: Lest we forget.