What is the allusion in "To Virgil" by Alfred Tennyson?

The primary allusion in "To Virgil" is to the fall of Rome. Virgil is  saluted as the poet who described the fall of Troy and the chronicler of Aeneas's travels, culminating in the legendary founding of the city of Rome.

Minor references include Dido, the queen of Carthage who committed suicide when Aeneas left her.