The Boston terrier breed of dogs has an interesting history that begins, of course, in Boston. It is believed that Boston terriers can be traced back to a dog named "Judge" who was sold to aman living

The Boston terrier breed of dogs has an interesting history that begins, of course, in Boston. It is believed that Boston terriers can be traced back to a dog named "Judge" who was sold to aman living in Boston named Hooper in 1870. Hooper's "Judge" was the first dog to have all the characteristics of the Boston terrier. Appropriately, he is considered the ancestor of almost all true modern Boston terriers.

Which sentence from the passsage contains a supporting detail that answers the question, When did this take place?