Some time early in 50 B.C. the two elder sons of M. Calpurnius Bibulus the Roman governor of Syria were killed in Egypt by milites Gabiniani, Roman soldiers left there by A. Gabinius – an earlier governor of Syria. What Bibulus' sons were doingin Egypt is a mystery, partly because we do not know how old they were; all we know about them is that they were outstandingly gifted or outstandingly beautiful, or both. The soldiers had been left in Egypt (basically as mercenaries) by Gabinius in 54 B.C. when hehad been bribed by Ptolemy XII Auletes to restore him to the throne from which he had been driven by his exasperated subjects. Why these particular troops took it into their heads to murder Bibulus' sons is another mystery, which we will touch upon, but our main concern here is the effect which the death of his sons had on Bibulus. Our contention is simply that the incident is part of a rarely documented example from the classical world of a clear mental breakdown in one prominent individual. In Bibulus' case it took the form of paralysing shock, followed by grief, depression, and a frenzy of sleepless activity in which he eventually wore himself to death. To understand how this operated in the way it did in this particular case, we need to understand Bibulus the man and his personal history.