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

16. After¹ these immortal achievements, Romulus held a review of his army at the ‘Caprae Palus’ in the Campus Martius. A violent thunder storm suddenly arose and enveloped the king in so dense a cloud that he was quite invisible to the assembly. From that hour Romulus was no longer seen on earth. [2] When the fears of the Roman youth were allayed by the return of bright, calm sun-shine after such fearful weather, they saw that the royal seat was vacant. Whilst they fully believed the assertion of the Senators, who had been standing close to him, that he had been snatched away to heaven by a whirlwind, still, like men suddenly bereaved, fear and grief kept them for some time speechless. [3] At length, after a few had taken the initiative, the whole of those present hailed Romulus as ‘a god, the son of a god, the King and Father of the City of Rome.’ They put up supplications for his grace and favour, and prayed that he would be propitious to his children and save and protect them. [4] I believe, however, that even then there were some who secretly hinted that he had been torn limb from limb by the senators-a tradition to this effect, though certainly a very dim one, has filtered down to us. [5] The other, which I follow, has been the prevailing one, due, no doubt, to the admiration felt for the man and the apprehensions excited by his disappearance. This generally accepted belief was strengthened by one man's clever device. The tradition runs that Proculus Julius, a man whose authority had weight in matters of even the gravest importance, seeing how deeply the community felt the loss of the king, and how incensed they were against the senators, came forward into the assembly and said: ‘Quirites! [6] at break of dawn, to-day, the Father of this City suddenly descended from heaven and appeared to me. [7] Whilst, thrilled with awe, I stood rapt before him in deepest reverence, praying that I might be pardoned for gazing upon him, ‘Go,’ said he, ‘tell the Romans that it is the will of heaven that my Rome should be the head of all the world. Let them henceforth cultivate the arts of war, and let them know assuredly, and hand down the knowledge to posterity, that no human might can withstand the arms of Rome.’’ [8] It is marvellous what credit was given to this man's story, and how the grief of the people and the army was soothed by the belief which had been created in the immortality of Romulus.