legate vs special messenger

legate

verb
  • To leave as a legacy. 

noun
  • The deputy of a provincial governor or general in ancient Rome. 

  • An ambassador or messenger. 

  • A deputy representing the pope, specifically a papal ambassador sent on special ecclesiastical missions. 

special messenger

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