What is the importance of allusions in "The Immorality of Verse" by Horace?
Lest you should think that verse shall die,
Which sounds the silver Thames along,
Taught on the wings of truth to fly
Above the reach of vulgar song;
Though daring Milton sits sublime,
In Spenser native Muses play;
Nor yet shall Waller yield to time,
Nor pensive Cowley's mortal lay.
Sages and chiefs long since had birth
Ere Caesar was, or Newton named;
These raised new empires o'er the earth,
And those, new heavens and systems framed.
Vain was the chief's, the sage's pride!
They had no poet, and they died.
In vain they schemed, in vain they bled!
They had no poet, and are dead
The allusions to other poets in this brilliant poem are used to support the central message of the poem, which is that immortality can only be truly gained through poetry. Note the final stanza, which seems to cement the argument of the speaker of this poem. Even though chieftains and leaders "raised new empires o'er the earth," their pride was all in "vain" because "they had not poet, and are dead." The message of this poem is very much that if we want to be immortal, or to have our name remembered throughout the history of mankind, we need to make sure that our name is enshrined in poetry.
This explains the second stanza and the way that each of the four poets mentioned, Milton, Spenser, Waller and Cowley, are shown to have stood the test of time. We still read them and we still talk about them and study their works. These poets will not "yield to time" but will endure throughout the centuries, proving that verse does not die, as the first line of this poem makes very clear.
The first thing to note here is that the poem is not actually by Horace, a Latin poet who lived in the first century BCE. The poem mentions the Thames, located in England, and Milton, Spenser, Cowley, and Newton, all of whom were born many centuries after Horace died.
The actual author of the poem is Alexander Pope, an eighteenth-century poet, writing in imitation of the themes of Horace's Ode IV.9. Horace's original ode mentions famous Greek poets such as Homer, Pindar, Simonides, Alcaeus, and Stesichorus. Thematically, though, both poems have a similar argument, namely that what makes people memorable, especially after their death, is a combination of great deeds and of artistic works such as poems which cause them to become fixed in cultural memory. We remember Helen's beauty or Odysseus's cleverness because of the Homeric epics, but other people equally attractive or clever have long been forgotten.
The point of the allusions is precisely to make us aware of how powerful poets are in creating cultural memory. Pope is suggesting that just as the ancient Greek poets cemented the reputation of ancient heroes for all time, so English poetry (including his own) will immortalize the great thinkers and leaders of England. The allusions to famous English poets such as Waller, Cowley, Milton, and Spenser are included as examples of poets whose verse will not "yield to time" (i.e. will never be forgotten). Thus the poets will preserve for all time the greatness of English leaders and thinkers.