oration vs rogation

oration

noun
  • A specific form of short, solemn prayer said by the president of the liturgical celebration on behalf of the people. 

  • A formal, often ceremonial speech. 

  • A lengthy speech or argument in a private setting. 

verb
  • To deliver an oration; to speak. 

rogation

noun
  • A deeply serious and somber prayer or entreaty. 

  • The demand, by the consuls or tribunes, of a law to be passed by the people; a proposed law or decree. 

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