Geoffrey Chaucer (1328-1400); so called by Dryden. Spenser calls
him “the pure well of English undefiled.” He was not the first English
poet, but was so superior to his predecessors that he laid the
foundation of a new era. He is sometimes termed “the day-starre,” and
Spenser the “sun-rise” of English poetry.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894