Titus Livius (Livy), The History of Rome, Book 4
Benjamin Oliver Foster, Ph.D., Ed.

21. When Marcus Cornelius Maluginensis and¹ Lucius Papirius Crassus were consuls, armies invaded the country of the Veientes and the Faliscans and drove off booty consisting of men and flocks; [2] they nowhere encountered their enemies in the fields nor met with any opportunity to give them battle; still, they besieged no cities, for a pestilence attacked the people. [3] And seditions were attempted at home, but not brought about, by Spurius Maelius, tribune of the plebs, who, imagining that the popularity of his name would enable him to stir up trouble, had appointed a day for the prosecution of Minucius, and had also proposed a law for confiscating the goods of Servilius Ahala, maintaining that [4??] Maelius had been circumvented by Minucius with false accusations, and flinging it up to Servilius that he had killed a citizen who had not been condemned. [5] These charges were even less regarded by the people than was their author. But the increasing virulence of the disease gave concern, and so did certain alarms and prodigies; [p. 327]in particular that it was frequently announced that² farm-buildings had been thrown down by earthquakes. A supplication was therefore offered up by the people under the direction of the duumviri.³

[6] The pestilence was worse next year, when Gaius Julius (for the second time) and Lucius Verginius were the consuls, and caused such fears and ravages in the City and the country that not only did [7??] no one go out beyond the Roman marches to pillage, nor either patricians or plebs have any thought of waging war, but the men of Fidenae, who at first had kept to their mountains or their city walls, actually came down into Roman territory, bent on plunder. [8] Then, when they had called in an army from Veii —for the Faliscans could not be driven into renewing the war either by the calamity of the Romans or the entreaties of their allies, —the two peoples crossed the Anio and set up their standards not far from the Colline Gate. [9] The consternation in the City was therefore no less than in the fields; the consul Julius disposed his troops on the rampart and walls, and Verginius took counsel with the senate in the temple of Quirinus. [10] It was resolved that Quintus Servilius, whose surname some give as Priscus, others as Structus, should be appointed dictator. Verginius delayed till he could consult his colleague; then, with his consent, he that night named the dictator, who appointed as his master of the horse Postumus Aebutius Helva.