basilica vs bishop’s seat

basilica

noun
  • A Christian church building having a nave with a semicircular apse, side aisles, a narthex and a clerestory. 

  • A Roman Catholic church or cathedral with basilican status, an honorific status granted by the pope to recognize its historical, architectural, or sacramental importance. 

bishop’s seat

How often have the words basilica and bishop’s seat occurred in a corpus of books? (source: Google Ngram Viewer )