"And it is of power and the man that I shall sing."
Aeneas lands in Latium, 2nd century AD relief
Creative Commons AttributionAeneas lands in Latium, 2nd century AD relief - Credit: Marie-Lan Nguyen/Wikimedia Commons

This is a reference to the famous first line of the Latin epic The Aeneid, written by Virgil under the patronage of the first emperor Augustus:

It is of arms and the man that I sing

The Aeneid is a poem of praise for Rome and its founder, the Trojan prince Aeneas. By referring to this great epic, Tiro is telling us that the story of Cicero, and its consequences, will be equally dramatic and important in the history of Rome.