What does ''more...than..." mean in the sentence? Which one is more/less?

Question

Thus ended a historic tragedy than which the stage possesses few of more striking dramatic interest and opportunities for histrionic effect.

What does ''more...than..." mean in the sentence? Which one is more/less? This sentence is extracted from ALBOIN AND ROSAMOND and the context is as follows.

As Helmichis left the bath he received a wine-cup from the hands of his treacherous wife, and lifted it to his lips. But no sooner had he tasted the liquor, and felt the shock that it gave his system, than he knew that he was poisoned. Death, a speedy death, was in his veins, but he had life enough left for revenge. Seizing his dagger, he pressed it to the breast of Rosamond, and by threats of instant death compelled her to drain the remainder of the cup. In a few minutes both the guilty partners in the death of Alboin had breathed their last.

When Longinus was, at a later moment, summoned into the room, it was to find his late guests both dead upon the floor. The poison had faithfully done its work. Thus ended a historic tragedy than which the stage possesses few of more striking dramatic interest and opportunities for histrionic effect.

Answer 1

The meaning is this:

Thus ended a historical tragedy. The stage possesses few [historical tragedies] of more striking dramatic interest and opportunities for histrionic effect than this one.

To show a simpler example of the structure, suppose a bakery sells pastries, and you are talking about a very sweet one, and want to sound like that author. You could say

This is a pastry, than which the bakery has few that are sweeter.

Unwrapping that,

The bakery has few pastries that are sweeter than this one.

Clarifying the use of the word "stage", it means the world of theater:
American Heritage Dictionary "stage"

c. The acting profession, or the world of theater. Used with the: The stage is her life.

So, in this case, the word "stage" is referring to all the plays that have ever been written. The author is claiming that the story he is telling is more dramatic than the plots of most plays that have been written, or as it was put, few that are more dramatic exist.

Answer 2

The sentence has the following meaning:

Thus ended (verb) a historic tragedy (subject); the stage posses few [tragedies] of more striking dramatic interest and opportunities for histrionic effect.

The structure is old-fashioned and artificial. "which" refers back to "a historic tragedy". In other words, "The stage possesses few other tragedies of more striking dramatic interest and opportunities for histrionic effect than the historic tragedy that ended in the manner you have just read."