The Aeneid is a Latin epic poem, written by Virgil between 29 and 19 BC, that tells the legendary story of Aeneas, a Trojan who travelled to Italy, where he became the ancestor of the Romans. The backstory is somewhat based on the Iliad and the Odyssey by the Greek poet Homer, so you may want to read that first. A general knowledge of Greek and Roman mythology and the geography of Italy, Greece, and the Mediterranean region would be helpful. Since the original was written in Latin, it is important to know what translation is being used. This translation into English verse by E. Fairfax Taylor contains extensive notes to explain many of the details, however you still may need to consult a dictionary for words like corslet, helm, sward, mead, etc. Also, the formatting for this Kindle edition was not the best. The prose translation by Fitzgerald may be easier to read, but would be far less interesting, I think.
It is easy to see why the Aeneid is considered an epic. It is hard for me to imagine writing nearly a thousand lines of poetry in twelve parts, but there is a lot to the story. Plenty of blow-by-blow battle action, the glory of victory and the agony of defeat, death itself and a visit to the afterlife:
"Those, who with hate a brother's love repaid, Or drove a parent outcast from their door, Or, weaving fraud, their client's trust betrayed; Those, who—the most in number—brooded o'er Their gold, nor gave to kinsmen of their store; Those, who for foul adultery were slain, Who followed treason's banner, or forswore Their plighted oath to masters, here remain, And, pent in dungeons deep, await their doom of pain." (Kindle Locations 4260-4264).
There is voyage at sea, misdirection, natural and supernatural disasters. Romance, athletic competition, devotion to parents, care for one's children, family heritage, religion and piety (devotion to the gods of Rome and ancient Troy).
The opponents that Aeneas faces are not such that he can easily prevail. Virgil presents Aeneus with worthy and noble opponents, as well as some examples of cowardice, plus meddling gods, goddesses, nymphs and fates. The poetry is rich with metaphor: an aged oak, a falcon, an eagle, a bull et cetera, are used to add descriptive color. Here is one example:
"Such furies urge him, and, ablaze with ire, His hot face sparkles, and his eyes burn bright, And from his eyeballs leaps the living fire; As when a bull, in prelude for the fight, Roars terribly, and fills the hinds with fright, And, butting at a chance-met tree, would try To vent his fury on his horns of might, And with his fierce hoofs flings the sand on high, And gores the empty air, and challenges the sky." (Locations 8396-8400).
Don't expect easy reading, but it may be enjoyable, if you like poetry and are fascinated by the ancient Roman world.