allay vs placate

allay

verb
  • To make quiet or put at rest; to pacify or appease; to quell; to calm. 

  • To alleviate; to abate; to mitigate. 

noun
  • Alleviation; abatement; check. 

placate

verb
  • To calm; to bring peace to; to influence someone who was furious to the point that they become content or at least no longer irate. 

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