Answer:
I believe it is diminishes.
Explanation:
Diminishes means to make smaller, to become smaller, or to lessen the authority or dignity of; to put down; to degrade; to abase; to weaken; to nerf (in gaming).
It may be softens, though, so apologies if I am incorrect.
The first sentence about Siamese cats is correct because the hypens are correctly placed where you pause when reading. The other answers have misplaced the hypens and they aren't in the appropriate place for pausing.
Answer: He believed there was a cultural continuum from pagan to Christian Rome.
