Pope’s poem is a mock-epic: that is, a poem that treats insignificant events in the manner of epic poetry. The opening couplet, which you quote, sets the stage for the entire poem, suggesting that the seizing of Belinda’s lock of hair (the “rape” referred to in the title of the poem) is a “trivial” event which nonetheless will inspire “mighty contests,” which the poem will record in true Homeric fashion. Pope knew Homer well—he made one of the great English translations of Homer. Compare Pope’s opening with the opening of his translation of the Iliad, for example:
Achilles' wrath, to Greece the direful spring
Of woes unnumber'd, heavenly goddess, sing!
That wrath which hurl'd to Pluto's gloomy reign
The souls of mighty chiefs untimely slain;
Whose limbs unburied on the naked shore,
Devouring dogs and hungry vultures tore.
Since great Achilles and Atrides strove,
Such was the sovereign doom, and such the will of Jove!
You’ll find that Pope follows Homer and the epic tradition in invoking the Muse to bless his poetic efforts. Pope also turns the bodies of the “slain chiefs” lying on the shore to Belinda who is sleeping in late (“Belinda still her downy pillow press’d”); the dogs that devour the corpses in Homer become Belinda’s lapdog (“Now lapdogs give themselves a rousing shake”).