Why is Chaucer called the "father of English poetry," in detail?

There
are several reasons why Chaucer is called the "father of English poetry." The first is
that histories of literature for many centuries had preferred, primarily for pedagogical
reasons, to create small canons of monumental poets rather than trying to teach a wider range of
poets. This was in part designed to create a shared cultural canon. More recent critics would
argue that there is no one "father" of English poetry but a cluster of
poets...