So fleet, so faint, so fair,
The Powers of Earth and Air
Fled from the folding-star of Bethlehem.
Apollo, Pan and Love,
And even Olympian Jove,
Grew weak, for killing Truth had glared on them.
In a manner more familiar perhaps in music than in poetry Shelley is echoing another poem, borrowing, as it were, Milton’s voice though not his words, making in fact a musical quotation, a poetical allusion of an exquisite felicity.
But by so doing he is necessarily restricting the number of the readers who will fully appreciate him.
Such allusions are a normal and regular part of the resources of all poets who belong to the literary tradition, that is to say, of the vast majority of poets in modern times. They are not often so unobtrusive and the place which they are given in the structure of the poem varies. Sometimes, as in this instance, a failure on the part of the reader has no important consequences. One familiar with the Hymn on the Morning of Christ’s Nativity will respond more fully and with a deeper sense of the situation; but a reader unfamiliar with it is not deprived of any major part of the poem. In other cases the loss is more serious. Another instance from Shelley will illustrate this, and it is interesting for its own sake. The Shape which guides the Chariot in the Triumph of Life is described and identified for the reader in a large degree through another Miltonic quotation or allusion:
A Shape
So sate within, as one whom years deform,
Beneath a dusky hood and double cape,
Crouching within the shadow of a tomb,
And o’er what seemed the head a cloud-like crape
Was bent.