This type of photography involves knowing more than one skill: landscape, indoor, architecture.
The easiest but probably the most spectacular photography is the landscape view of a castle/palace. Most of them are located in mountain regions or near a lake/river. Think for example at the castles on the Rhin Ri’ver in Germany. Considering the century when these were build, you may encounter a dig around them or a big fancy gate and colorful gardens. (Check for example Versailles in France, near Paris)
As for indoor, even if they have tall walls, usually they are very dark. The use of flash is required for capturing the furniture inside the royal rooms.
Architecture is represented by sculptures and statues. In the morning or evening the light suits better every shadow of the forms.
Shooting holy places from outside is similar with castles and palaces, only that I recommend a vertical composition. (The holy symbol on the top should fit in the picture)
As for the inside, the paintings, statues, painted glass and the above candelabra with curved upper wall are the usual subjects.
Of course flash is recommended (however not for more than 3m distance) but normally it is not allowed. A tripod and high ISO plus an increment or two for exposure compensation/bracketing will help. The latest in this domain are the indoor HDR images. (Works great for shooting against painted glass) Also, when focusing on the altar, try a vertical panorama to capture it with the above candelabra.
A specific lens type for architecture, a wide lens will capture more of the room in one shoot, however, with some distortion.
In the end I also give a tip on shooting the siluet of a representative part of the building: in my example, the bell over the city landscape framed by the bells room curved gate.