Titus Livius (Livy), The History of Rome, Book 1
Rev. Canon Roberts, Ed.

31. This¹ victory threw great lustre upon the reign of Tullus, and upon the whole State and added considerably to its strength. At this time it was reported to the king and the senate that there had been a shower of stones on the Alban Mount. [2] As the thing seemed hardly credible, men were sent to inspect the prodigy, and whilst they were watching, a heavy shower of stones fell from the sky, just like hailstones heaped together by the wind. [3] They fancied, too, that they heard a very loud voice from the grove on the summit bidding the Albans celebrate their sacred rites after the manner of their fathers. These solemnities they had consigned to oblivion, as though they had abandoned their gods when they abandoned their country and had either adopted Roman rites or, as sometimes happens, embittered against Fortune, had given up the service of the gods. [4] In consequence of this prodigy, the Romans, too, kept up a public religious observance for nine days, either —as tradition asserts —owing to the voice from the Alban Mount, or because of the warning of the soothsayers. [5] In either case, however, it became permanently established whenever the same prodigy was reported; a nine days' solemnity was observed.

Not long after a pestilence caused great distress, and made men indisposed for the hardships of military service. The warlike king, however, allowed no respite from arms; he thought, too, that it was more healthy for the soldiery in the field than at home. [6] At last he himself was seized with a lingering illness, and that fierce and restless spirit became so broken through bodily weakness, that he who had once thought nothing less fitting for a king than devotion to sacred things, now suddenly became a prey to every sort of religious terror, and filled the City with religious observances. [7] There was a general desire to recall the condition of things which existed under Numa, for men felt that the only help that was left against sickness was to obtain the forgiveness of the gods and be at peace with heaven.

[8] Tradition records that the king, whilst examining the commentaries of Numa, found there a description of certain secret sacrificial rites paid to Jupiter Elicius: he withdrew into privacy whilst occupied with these rites, but their performance was marred by omissions or mistakes. Not only was no sign from heaven vouchsafed to him, but the anger of Jupiter was roused by the false worship rendered to him, and he burnt up the king and his house by a stroke of lightning.

Tullus had achieved great renown in war, and reigned for two-and-thirty years.