In the time of Numa Pompilius by a divine miracle there fell from heaven into Rome a vermilion-coloured shield, for the which cause and augury the Romans took that ensign for their arms, and afterwards added S.P.Q.R. in letters of gold, signifying Senate of the People of Rome; the same ensign they gave to all the cities which they built, to wit, vermilion. Thus did they to Perugia, and to Florence, and to Pisa; but the Florentines, because of the name of Fiorinus and of the city, charged it with the white lily; and the Perugians sometimes with the white griffin; and Viterbo kept the red field, and the Orvietans charged it with the white eagle. It is true that the Roman lords, consuls and dictators, after that the eagle appeared as an augury over the Tarpeian rock, to wit, over the treasure chamber of the Capitol, as Titus Livius makes mention, added the eagle to their arms on the ensign; and we find that the consul Marius in the battle of the Cimbri had on his ensigns the silver eagle, and a similar ensign was borne by Catiline when he was defeated by Antonius in the parts about Pistoia, as Sallust relates. And the great Pompey bore the azure field and silver eagle, and Julius Caesar bore the vermilion field and golden eagle, as Lucan makes mention in verse, saying, Signa pares aquilas, et pila minantia pilis. But afterwards Octavianus Augustus, his nephew and successor, changed it, and bore the golden field and the eagle natural, to wit, in black colour, signifying the supremacy of the Empire, for like as the eagle surpasses every other bird, and sees more clearly than any other creature, and flies as high as the heaven of the hemisphere of fire, so the Empire ought to be above every other temporal sovereignty. And after Octavianus all the Roman emperors have borne it in like manner; but Constantine, and after him all the other Greek emperors, retained the ensign of Julius Caesar, to wit, the vermilion field and golden eagle, but with two heads. We will leave speaking of the ensigns of the Roman commonwealth and of the Emperors, and we will return to our subject concerning the doings of the city of Florence. Sec. 41.--_How the city of Florence became the Treasure-House of the Romans and the Empire._ Sec. 42.--_How the Temple of Mars, which is now called the Duomo of S. Giovanni, was built in Florence._