besiegement vs descent

besiegement

noun
  • The act of besieging, or the state of being besieged. 

descent

noun
  • A falling upon or invasion. 

  • A particular extension of the idea of gluing. 

  • A sloping passage or incline. 

  • A drop to a lower status or condition; decline. 

  • Lineage or hereditary derivation. 

  • An instance of descending; act of coming down. 

  • A way down. 

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