Philo, On Abraham
33.182 (tr. C.D. Yonge):
And they say that to this very day the Gymnosophists among the Indians, when that long or incurable disease, old age, begins to attack them, before it has got a firm hold of them, and while they might still last for many years, kindle a fire and burn themselves.
Ἰνδῶν δὲ τοὺς γυμνοσοφιστὰς ἄχρι νὺν, ἐπειδὰν ἄρχηται καταλαμβάνειν ἡ μακρὰ καὶ ἀνίατος νόσος, τὸ γῆρας, πρὶν βεβαίως κρατηθῆναι, πυρὰν νήσαντας ἑαυτοὺς ἐμπιπράναι, δυναμένους ἔτι πρὸς πολυετίαν ἴσως ἀντισχεῖν.
Curtius Rufus 8.9.31-32 (tr. J.C. Rolfe; on the Indians):
 Who would believe that amid such vices there would be regard for philosophy? There is one rude and hideous class which they call sages.  These consider it glorious to anticipate the day of fate, and those whose life is feeble or whose health is impaired give orders to be burned alive; to wait for death they regard as a disgrace to life, and no honour is paid to the bodies of those who die of old age; they believe that the fire is sullied unless it receives them while still breathing.
 quis credat inter haec vitia curam esse sapientiae? unum agreste et horridum genus est, quod sapientes vocant.  apud hos occupare fati diem pulchrum et vivos se cremari iubent, quibus aut segnis aetas aut incommoda valitudo est; expectatam mortem pro dedecore vitae habent, nec ullus corporibus, quae senectus solvit, honos redditur; inquinari putant ignem, nisi qui spirantes recipit.
Silius Italicus 1.225-228 (tr. J.D. Duff; on the Spaniards):
That people recks little of life, and they are most ready to anticipate death. For, when a man has passed the years of youthful strength, he cannot bear to live on and disdains acquaintance with old age; and his span of life depends on his own right arm.
prodiga gens animae et properare facillima mortem.
namque ubi transcendit florentis viribus annos,
impatiens aevi spernit novisse senectam,
et fati modus in dextra est.
Silius Italicus 3.328-331 (tr. J.D. Duff; on the Cantabrians in Spain):
This people, when disabled by white old age, find a strange pleasure in cutting short the years of weakness by an instant death, and they
refuse life except in arms. For war is their only reason for living, and they scorn a peaceful existence.
mirus amor populo, cum pigra incanuit aetas,
imbelles iam dudum annos praevertere fato
nec vitam sine Marte pati: quippe omnis in armis
lucis causa sita, et damnatum vivere paci.
329 fato Bentley: saxo codd.; taxo Ruperti (i.e. veneno)