The ancient temple contained the Emperor's Blade contained with in a sealed package which contained a nullentropy field. On the blade was the blood from the assassination attempt nearly 5000 years earlier by Count Hasimir Fenring, who had tried to kill the former Emperor on Arrakis.
Ardeth was the guardian of the Blade when Enhanced Face Dancer leader, Khrone, found out about the Temple and Blade; and brought Uxtal there a short while later. Ardeth protested Khrone and Uxtal handling the Blade, and when Khrone attempted to take the Blade from the sanctuary, Ardeth struggled to get free. Khrone having had enough of her protestations, snapped Ardeth's neck, and she died.
The blood and other cellular matter on the Blade was used to create a clone of Paul Atreides, for the Thinking Machines Ultimate Kwisatz Haderach plan. The clone that Uxtal created in Bandalong on Tleilax was called Paolo.