guild vs seat of learning

guild

noun
  • A corporation. 

  • A group or association mainly of tradespeople made up of merchants, craftspeople, or artisans for mutual aid, particularly in the Middle Ages. 

  • A group of diverse species that share common characteristics or habits. 

  • An organized group of players who regularly play together in a multiplayer game. 

seat of learning

noun
  • An educational institution. 

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