convene vs herd together

convene

verb
  • To come together, as in one body or for a public purpose; to meet; to assemble. 

  • To make a convention; to declare a rule by convention. 

  • To cause to assemble; to call together; to convoke. 

  • To come together; to meet; to unite. 

  • To summon judicially to meet or appear. 

herd together

verb
  • To push people or animals into a group, as a herd. 

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