This Quarrel first began (as I have heard it affirmed by an old Dweller in the Neighbourhood) about a small Spot of Ground, lying and being upon one of the Two tops of the Hill Parnassus; the highest and largest of which had, it seems, been time out of Mind, in quiet Possession of certain Tenants, called the Antients; And the other was held by the Moderns. But, these disliking their present Station, sent certain Ambassadors to the Antients, complaining of a great Nuisance, how the Height of that Part of Parnassus, quite spoiled the Prospect of theirs, especially towards the East; and therefore, to avoid a War, offered them the Choice of this Alternative; either that the Antients would please to remove themselves and their Effects down to the lower Summity, which the Moderns would graciously surrender to them, and advance in their Place; or else the said Antients will give leave to the Moderns to come with Shovels and Mattocks, and level the said Hill, as low as they shall think it convenient. To which the Antients made Answer: How little they expected such a Message as this, from a Colony, whom they had admitted out of their own Free Grace, to so near a Neighbourhood. (Battle of the Books)

Basic set up:

One of the big debates during Swift's time was whether ancient Greek and Roman learning and knowledge were superior to modern learning and knowledge. Here, Swift explains the debate in terms of the Ancients and Moderns fighting each other over a spot of land. Later in the satire, he actually turns this debate into a literal battle between books fighting each other in a library.

We told you those Augustans were obsessed with the ancients.

We see two camps here: one is made up of scholars and writers who believed that classical knowledge—all that stuff found in the work of ancients like Homer and Aristotle—would never be surpassed.

The other camp believes the opposite: they think that the advances in knowledge being made during their own time surpass those made by the ancients.

Swift is basically lampooning both camps. He depicts the debate between these two sides as a battle between Ancient and Modern "tenants" of a neighborhood squabbling over some land. Way to take the wind out of their sails and make them look ridiculous, right?

Satire is powerful in part because it's so funny. By turning the debate over ancient vs. modern knowledge into a silly fight over a spot of land, Swift makes the whole debate seem absurd. He's showing his readers how ridiculous and trivial this argument really is.

After all, is there a right answer to the question of whether classical knowledge is superior to modern knowledge? Surely we learn some important things from the classics. But isn't it also true that modern books make some pretty important contributions to our collective knowledge? Why choose just one or the other?