Originally Posted by
Septaryeth
You're pretty much on the right spot.
Basically the ring gives its owner authority over demons and demonic power.
Both King Solomon and Pope used the ring to build structures. Pope also used it to lift the curse the infamous Marquis placed on the village years ago.
The Marquis somehow survived and became immortal, which might not be so surprising given his vast knowledge of the supernatural.
Although it is still uncertain how it was lost from the Pope and fall into the Marquis' hands,
(given his status as the ultimate collector and negotiator he may have strike a deal to obtain it),
the Marquis used the ring to enslave demons, and supposedly using their power to expand his collections, or just for the vanity of it..