The Gold of Tolosa (also the aurum Tolosanum) existed as a hoard of treasures plundered from Greece (allegedly the sanctuary of Apollo at Delphi) in 279 BC by Gallic invaders of the Volcae (often denoted incorrectly as Galatians, despite the later migration of some Volcae Tectosagi to Galatia). It was often noted that, during the siege of Apollo's sanctuary at Delphi, the Gallic leader, Brennus, was badly wounded (many contemporary sources state some kind of divine intervention, and the battle was lost against a combined force of Thracians, Macedonians, Triballi and Illyrians). Many, after their fortunes reversed, retreated back into the Balkans, some to the Volcae heartlands, and many others back to Gaul itself, dumping their plunder into the lakes near Tolosa (modern-day Toulouse), believing that the loot was cursed. The faltering of Brennus's great expedition, however, helped create the Gallic exclaves around Tylis and in Galatia, the latter of which remaining de facto independent for centuries to come.
For the curse to be lifted, according to Celtic paganism, the treasure had to be offered back to the Celtic gods, and so was left in the lakes. Other guilty warriors hid their treasure in the vegetation around the lakes. The lakes at Tolosa were used many years thereafter as a place of pagan worship, but nobody (who believed in the curse) dared recover the glinting treasures from the sandy lake bed. Some of the treasures, however, did find their way into the temples of Tolosa, but the same religious taboo of their theft still presided.
And it is further said that the [Volcae] Tectosages shared in the expedition to Delphi; and even the treasures that were found among them in the city of Toulouse by Caepio, a general of the Romans, were, it is said, a part of the valuables that were taken from Delphi, although the people, in trying to consecrate them and propitiate the god, added thereto out of their personal properties, and it was on account of having laid hands on them that Caepio ended his life in misfortunes — for he was cast out by his native land as a temple-robber, and he left behind as his heirs female children only, who, as it turned out, became prostitutes, as Timagenes has said, and therefore perished in disgrace. [Note that Strabo here is mistaken, since Caepio did have a son, the maternal grandfather of Marcus Junius Brutus, the principal assassin of Julius Caesar.]