firman vs ruling

firman

noun
  • A royal decree issued by a sovereign in certain historical Islamic states, especially by the Sultan of Turkey. 

ruling

noun
  • An order or a decision on a point of law from someone in authority. 

adj
  • That rules; predominant; chief; reigning; controlling. 

How often have the words firman and ruling occurred in a corpus of books? (source: Google Ngram Viewer )