gain mastery over vs overpower

gain mastery over

overpower

verb
  • To make excessively powerful. 

  • To excel or exceed in power; to cause to yield; to subdue. 

  • To subdue someone by superior force. 

  • To render imperceptible by means of greater strength, intensity, etc. 

How often have the words gain mastery over and overpower occurred in a corpus of books? (source: Google Ngram Viewer )