royalism

Support of monarchy or of a particular monarch.

The principles or cause of royalty; attachment to a royal government or cause.

the principles or conduct of royalists.

Impassioned allegiance to or advocacy of the establishment, maintenance, and/or interests of a particular king, royal house, or kingly dynasty; sometimes extended to the same of a non-royal (i.e., grand ducal, imperial, or other) family or sovereign; often contrasted with monarchism.

adherence or attachment to a monarchy or to the principle of monarchal government