ancestry vs gens

ancestry

noun
  • A series of ancestors or progenitors; lineage, or those who compose the line of natural descent. 

  • Condition as to ancestors; ancestral lineage; hence, birth or honorable descent. 

gens

noun
  • A tribal subgroup whose members are characterized by having the same descent, usually along the male line. 

  • A legally defined unit of Roman society, being a collection of people related through a common ancestor by birth, marriage or adoption, possibly over many generations, and sharing the same nomen gentilicium. 

  • A host-specific lineage of a brood parasite species.^([W]) 

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