Having been there several years ago I can recommend a visit.
I was given the following background to the story (obviously having been a tourist it was embellished a little)
Normally when an Emperor died his loyal army was sacrificed so that they could protect him in the afterlife.
Either the Emperor was a bit more of a humanitarian than the previous ones or else he realised that his army didn't really fancy the idea. He decided to commision a life-like image of every one of his soldiers.
The result is only done justice if you can visit the site itself.