burgomaster vs magistrate

burgomaster

noun
  • The mayor, or head magistrate, of a town in the Netherlands, Belgium, Germany and certain other countries. 

magistrate

noun
  • A high official of the state or a municipality in ancient Greece or Rome. 

  • A comparable official in medieval or modern institutions. 

  • A master's degree. 

  • A judicial officer with limited authority to administer and enforce the law. A magistrate's court may have jurisdiction in civil or criminal cases, or both. 

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