Titus Livius (Livy), The History of Rome, Book 1
Benjamin Oliver Foster, Ph.D., Ed.

5. They say that the Palatine was even then the scene of the merry festival of the Lupercalia which we have to-day, and that the hill was named Pallantium, from Pallanteum, an Arcadian city, and then Palatium.¹ [2] There Evander, an Arcadian of that stock, who had held the place many ages before the time of which I am writing, is said to have established the yearly rite, derived from Arcadia, that youths should run naked about in playful sport, doing honour to Lycaean Pan, whom the Romans afterwards called Inuus. [3] When the young men were occupied in this celebration, the rite being generally known, some robbers who had been angered by the loss of their plunder laid an ambush for them, and although Romulus successfully defended himself, captured Remus and delivered up their prisoner to King Amulius, even lodging a complaint against him. [4] The main charge was that the brothers made raids on the lands of Numitor, and pillaged them, with a band of young fellows which they had got together, like an invading enemy. [5] So Remus was given up to Numitor to be punished. From the very beginning Faustulus had entertained the suspicion that they were children of the royal blood that he was bringing up in his house; for he was aware both that infants had been exposed by order of the king, and that the time when he had himself taken up the children exactly coincided with that event. But he had been unwilling that the [p. 23]matter should be disclosed prematurely, until opportunity offered or necessity compelled. [6] Necessity came first; accordingly, driven by fear, he revealed the facts to Romulus. It chanced that Numitor too, having Remus in custody, and hearing that the brothers were twins, had been reminded, upon considering their age and their far from servile nature, of his grandsons. The inquiries he made led him to the same conclusion, so that he was almost ready to acknowledge Remus. Thus on every hand the toils were woven about the king. [7] Romulus did not assemble his company of youths —for he was not equal to open violence —but commanded his shepherds to come to the palace at an appointed time, some by one way, some by another, and so made his attack upon the king; while from the house of Numitor came Remus, with another party which he had got together, to help his brother. So Romulus slew the king.