When the Gaulish warlord Brennus led his army through the Greek defences at Thermopylae and into a full-on assault on Delphi in 279BC, he was attacking perhaps the most important and wealthy religious centre of ancient Greece, notable for its oracular priestesses who apparently communed with the solar god Apollo in order to answer the questions of suppliants. These suppliants came from across the known world and beyond, and bought great wealth and honour to the sanctuary and its city, deep in the Greek highlands. Although there are no surviving contemporary records of this exceptional assault by the Celtic army, the 1stC Gallo-Roman author Gnaeus Pompeius Trogus of the Vocontii of Gallia Narbonensis wrote about the attack some 200 years later in his ‘Phillipic History‘ (of the Macedonian dynasty and its aftermath) which survives in a slightly later Epitome by Roman author, Justin. Given the role of southern Gauls in tne campaign (the Volcae Tectosages Belgic group settled or returned there after the event – reputedly with great wealth) it seems that Pompeius Trogus’ account is worth paying attention to, albeit embellished with the idea that those who attack holy sites pay with their lives… In Book 25 of Justin’s ‘Epitome’, we learn the following:
“… The Gauls, when the land that had produced them was unable, from their excessive increase of population, to contain them, sent out three hundred thousand men, as a sacred spring, to seek new settlements. Of these adventurers part settled in Italy, and took and burnt the city of Rome; and part penetrated into the remotest parts of Illyricum under the direction of a flight of birds (for the Gauls are skilled in augury beyond other nations) making their way amidst great slaughter of the barbarous tribes, and fixed their abode in Pannonia. They were a savage, bold, and warlike nation, and were the first after Hercules (to whom that undertaking procured great admiration for his valour, and a belief in his immortality), to pass the unconquered heights of the Alps, and places uninhabitable from excess of cold. After having subdued the Pannonians, they carried on various wars with their neighbours for many years. Success encouraging them, they betook themselves, in separate bands, some to Greece, and some to Macedonia, laying waste all before them with the sword. Such indeed was the terror of the Gallic name, that even kings, before they were attacked, purchased peace from them with large sums of money…”
He goes on to describe the defeat and death of the Macedonian king Ptolemy Keraunos and his army by the theophorically-titled Celtic warlord, Belgius. Another Gaulish chieftain, Brennus, appears to have then entered the fray to acquire his own share of the wealth of the crumbling Empire’s homelands:
“…In the meantime Brennus, under whose command a part of the Gauls had made an irruption into Greece, having heard of the success of their countrymen, who, under the leadership of Belgius, had defeated the Macedonians, and being indignant that so rich a booty, consisting of the spoils of the east, had been so lightly abandoned, assembled an army of a hundred and fifty thousand foot and fifteen thousand horse, and suddenly invaded Macedonia. As he was laying waste the fields and villages, Sosthenes met him with his army of Macedonians in full array, but being few in number, and in some consternation, they were easily overcome by the more numerous and powerful Gauls; and the defeated Macedonians retiring within the walls of their cities, the victorious Brennus, meeting with no opposition, ravaged the lands throughout the whole of Macedonia. Soon after, as if the spoils of mortals were too mean for him, he turned his thoughts to the temples of the immortal gods, saying, with a profane jest, that “the gods, being rich, ought to be liberal to men.” He suddenly, therefore, directed his march towards Delphi, regarding plunder more than religion, and caring for gold more than for the wrath of the deities, “who,” he said, “stood in no need of riches, as being accustomed rather to bestow them on mortals.”
The temple of Apollo at Delphi is situate on Mount Parnassus, on a rock steep on all sides. A concourse of people, who, collecting from the parts around, through veneration for the majesty of the god, settled on the rock, formed a city there. Thus, not walls, but precipices, not defences formed by the hand, but by nature, protect the temple and the city; so that it is utterly uncertain whether the strength of the place, or the influence of the deity residing in it, attracts more admiration. The central part of the rock falls back in the shape of an amphitheatre; and, in consequence, if ever shouts are raised, or if the noise of trumpets is mingled with them, the sound, from the rocks echoing and re-echoing to one another, is heard many times repeated, and louder than it was made at first. This effect, on those who are ignorant of its cause, and are struck with wonder at it, produces a greater awe of the power of the god. In the winding of the rock, about half way up the hill, there is a small plain, and in it a deep fissure in the ground, which is open for giving oracles; for a cold exhalation, driven upwards by some force, as it were by a wind, produces in the minds of the priestesses a certain madness, and compels them, filled with the influence of the god, to give answers to such as consult them. Hence many rich presents of kings and nations are to be seen there, which, by their magnificence, testify the grateful feelings of those that have paid their vows, and their belief in the oracles given by the deity.
Brennus, when he came within sight of the temple, deliberated for some time, whether he should at once make an attempt upon it, or should allow his soldiers, wearied with their march, a night to refresh themselves. The captains of the Emanus and Thessalorus, who had joined him for a share in the booty, advised that “no delay should be made,” while the enemy were unprovided for defence, and the alarm at their coming still fresh; that in the interval of a night, the courage of the enemy would perhaps revive, and assistance come to them; and that the approaches, which were now open, might be blocked up. But the common soldiers, when, after a long endurance of scarcity, they found a country abounding with wine and other provisions, had dispersed themselves over the fields, rejoicing as much at the plenty as if they had gained a victory, and leaving their standards deserted, wandered about to seize on everything like conquerors. This conduct gave some respite to the Delphians. At the first report that the Gauls were approaching, the countrypeople are said to have been prohibited by the oracle from carrying away their corn and wine from their houses. The salutariness of this prohibition was not understood, until, through this abundance of wine and other provisions being thrown in the way of the Gauls, as a stop to their progress, reinforcements from their neighbours had time to collect. The Delphians, accordingly, supported by the strength of their allies, secured their city before the Gauls, who clung to the wine-skins, on which they had seized, could be recalled to their standards. Brennus had sixty-five thousand infantry, selected from his whole army; of the Delphians there were not more than four thousand; in utter contempt of whom, Brennus, to rouse the courage of his men, pointed to the vast quantity of spoil before them, declaring that the statues, and four-horse chariots, of which a great number were visible at a distance, were made of solid gold, and would prove greater prices when they came to be weighed than they were in appearance.
The Gauls, animated by these assertions, and disordered, at the same time, with the wine which they had drunk the day before, rushed to battle without any fear of danger. The Delphians, on the other hand, placing more confidence in the god than in their own strength, resisted the enemy with contempt, and, from the top of the hill, repelled the Gauls as they climbed up, partly with pieces of rock, and partly with their weapons. Amidst this contest between the two, the priests of all the temples, as well as the priestesses themselves, with their hair loose, and with their decorations and fillets, rushed, trembling and frantic, into the front ranks of the combatants, exclaiming that “the god was come; that they had seen him leap down into his temple through the opening roof; that, while they were all humbly imploring aid of the deity, a youth of extraordinary beauty, far above that of mortals, and two armed virgins, coming from the neighbouring temples of Diana and Minerva, met them; that they had not only perceived them with their eyes, but had heard also the sound of a bow and the rattling of arms;” and they therefore conjured them with the strongest entreaties, “not to delay, when the gods were leading them on, to spread slaughter among the enemy, and to share the victory with the powers of heaven.” Incited by these exhortations, they all rushed eagerly to the field of battle, where they themselves also soon perceived the presence of the divinity; for a part of the mountain, broken off by an earthquake, overwhelmed a host of the Gauls and some of the densest bodies of the enemy were scattered abroad, not without wounds, and fell to the earth. A tempest then followed, which destroyed, with hail and cold, those that were suffering from bodily injuries. The general Brennus himself, unable to endure the pain of his wounds, ended his life with his dagger. The other general, after punishing the advisers of the war, made off from Greece with all expedition… “
Pausanias (Description of Greece, 2ndC CE) added greater detail to his own version of the story, claiming that the disorder that led to the apparent defeat of Brennus and his army was caused by an apparent outbreak of madness within the Gaulish camp which caused them to fight among themselves…
“… At the beginning of the fight the Gauls offered a spirited resistance, especially the company attached to Brennus, which was composed of the tallest and bravest of the Gauls, and that though they were shot at from all sides, and no less distressed by the frost, especially the wounded men. But when Brennus himself was wounded, he was carried fainting from the battle, and the barbarians, harassed on all sides by the Greeks, fell back reluctantly, putting to the sword those who, disabled by wounds or sickness, could not go with them.
They encamped where night overtook them in their retreat, and during the night there fell on them a “panic.” For causeless terrors are said to come from the god Pan. It was when evening was turning to night that the confusion fell on the army, and at first only a few became mad, and these imagined that they heard the trampling of horses at a gallop, and the attack of advancing enemies; but after a little time the delusion spread to all.
So rushing to arms they divided into two parties, killing and being killed, neither understanding their mother tongue nor recognizing one another’s forms or the shape of their shields. Both parties alike under the present delusion thought that their opponents were Greek, men and armour, and that the language they spoke was Greek, so that a great mutual slaughter was wrought among the Gauls by the madness sent by the god…”

Considering both accounts, we can see that Brennus’ previously highly disciplined and motivated army arrived at Delphi after a string of significant earlier victories, and plundered (or were given) some wine and subsequently fell into disarray, eventually being repelled. Both accounts agree on a certain amount of chaos breaking out, but Pausanias states that the Gauls suffered a mass outbreak of some kind of hallucinatory and delusional psychosis and paranoia. Assuming that he is not speaking figuratively of the weapons of the god Apollo (divine madness) it would appear that the Gauls were affected by the Delphian wine, which was obviously no ordinary wine…
Herba Appolinaris:

Hyoscyamus Niger
It is likely that Brennus’ army (or a significant part of it) fell prey to the effects of wine laced with the mind-bending herb Hyoscyamus Niger, known in English as Henbane, in Spanish as Beleno, and in German as Bilsenkraut. The ancients (eg – Pedanius Dioscorides (De Materia Medica, Book 4, 1stC CE, also Pliny the Elder) knew it as Herba Appolinaris – the herb of Apollo. In fact, Dioscorides tells us of the many names for it across the known world:
It is also called dioscyamos, pythonion, adamas, adamenon, hypnoticum, emmanes, atomon, or dithiambrion; Pythagoras and Osthenes call it xeleon, Zoroastres, tephonion, the Romans, inanaoentaria, some, Apollinaris, the Magi, rhaponticum, the Egyptians, saptho, the Thuscans, phoebulonga, the Gauls, bilinuntiam, and the Dacians, dieliam.
That Dioscorides gives the Gaulish word as ‘Bilinuntiam’ is often taken as indicative of a concordance between the gods Apollo and the Celtic deity Belenos, and thus it would seem of interest to those who are intrigued by the genesis of the cultural movement of the Celtic ‘tribes’ referred to under the umbrella term Belgae who were somehow linked to the events of 279BC. Dioscorides’ reference to the name ‘pythonian’ for Hyoscyamus also appears to be a reference to this oracular usage, although the myth maintained at Delphi was that priestesses inhaled the exhalations of an ancient vent in the ground, no doubt supposed to conduct the fumes of the decaying corpse of the giant Python killed by Apollo. The fact that Henbane is also known as ‘Stinking Henbane’ due to its unpleasant odour adds to the likelihood that it was responsible for the mind-bending oracles of the Pythia.

Greek tetradrachm depicting Apollo the archer with the Python and the Delphic tripod
Toxicity of Hyoscyamus goes from mild drunkenness to a total confusion, agitation and frenzy, and from there easily into overdosage and death. Obviously, the Pythia (priestesses of the Apollonian oracle) would have been experts at dosing themselves, and must have possessed a standardised preparation which they consumed. It is possible that they could have inhaled the vapours from burning seeds, but given the accounts of Pausanias and Pompeius Trogus/Justin about the chaos that afflicted Brennus’ army in 279BC it is just as likely that they consumed it in wine. Pausanias’ comment that Brennus died of drinking undiluted wine could well be an allusion to this, in fact. Pompeius Trogus states that the leaders at Delphi ordered that the Gauls be given free access to the wine and food of the city, so a deliberate poisoning may well have occurred…
Berserkers?:
The reputation for bravery and ferocity of some Celtic warriors was commented on by a number of Roman authors – not in the least to allow themselves to congratulate their own soldiers for defeating them. The same ferocity among ‘barbarian’ warriors next receives comment when Christian Europeans encountered the warring aspect of their pagan neighbours from the north during the ‘Viking’ era, this time in the form of the ‘Berserkr‘ (lit. ‘Bear Skin’) warriors. These were men who had dedicated themselves to Odin, their god of battle. The Anglo-Saxon equivalent was Wodan – a name recognisably connected with the Old/Middle English word ‘Wod(e)’, meaning madness or frenzy. It has been suggested that Henbane is a likely drug that could have been used to induce a visionary or frenzied state in Berserkr warriors, and evidence of Henbane seeds among possessions buried in pagan graves (eg – Fyrkat, Denmark) has been used to reinforce this suggestion (although to my mind they could equally have been used for preventing sea-sickness!). Further to this, there was a tradition in Germany and Bohemia of brewing beer using Henbane, suggesting that ‘Pilsener’ was a name fortuitously apprehended by the burghers of Plzen in Bohemia with which to brand their own pseudo-eponymous mass-produced beer in the 19thC, albeit without the ‘Pilsenkraut’ additives. Bohemia, was of course named after the Celtic Boii tribal federation who were undoubtedly involved in the Balkan, Greek and Anatolian Celtic campaigns of the 4th/3rdC BCE.

The ‘visionary’ man holding a torc and serpent (Gundestrup cauldron – late Celtic iron age). Compare this image to the Delphian tetradrachm above…
Bearing in mind my suggested concordances of the Celtic god Belenos with a number of medieval-era late pagan gods and mythological characters from northern and eastern Europe, the association with Apollo, and similarities between the Pythonian myth and the conception of the pagan Scandinavian universe from the Icelandic Edda texts, a picture begins to emerge of the survival and transformation of an Iron Age visionary religion which reached its height in the 3rdC BCE and which survived Romanisation in the Germanic, Slavic and Scandinavian regions…