Matthew Arnold believed that Geoffrey Chaucer is not a truly great poet because his poetry lacks "high seriousness."
In The Study of Poetry (1880), Arnold acknowledged Chaucer’s brilliance in storytelling, vivid character depiction, and poetic skill. However, he argued that Chaucer’s tone is often light, humorous, and lacking the deep moral gravity that he considered essential for truly great poetry. Unlike poets such as Homer, Dante, Shakespeare, and Milton, Chaucer did not consistently engage with profound universal truths in a serious manner.
Despite this, Arnold still admired Chaucer as the father of English poetry, recognizing his literary genius while placing him just below the highest rank of poets.