How to handle royalty as authors ??

I want the a king to appear as the author in a bibliography eg 

Charles IX. Book title. Year etc.  

But, his name keeps getting abbreviated to IX, C. as if IX was his last name … 

Thanks in advance 


Is “Charles IX” the complete name?  Just wondering as there are different “Charles IX” throughout history.  In any event just treat his name like an organization by adding a comma in the Author field which will then display the complete name:

Charles IX,