Valerius Maximus, Wonndrous Deeds and Sayings 2.6.10
“This ancient custom of the Gauls returns to my mind as I leave their walls: The story goes that they used to loan money which was scheduled to be repaid in the underworld, because they considered human souls to be immortal. I would call them fools if they didn’t believe the same thing wearing pants as Pythagoras did wrapped in his cloak.”
Horum moenia egresso vetus ille mos Gallorum occurrit,quo[s] memoria proditum est pecunias mutuas, quae iis apud inferos redderentur, da<ri soli>tas, quia persuasum habuerint animas hominum immortales esse. dicerem stultos, nisi idem bracati sensissent quod palliatus Pythagoras credidit.