Ammianus Marcellinus Res Gestae 29.5.54

[54] And since he had learned through Masilla of the secret negotiations, he saw that in his extremity only one remedy was left, and decided by a voluntary death to spurn with his foot the desire to live. Accordingly, having purposely filled his guards with wine and made them drunk, and in the silence of the night they were buried in sound sleep, he himself, kept awake by fear of the trouble which hung over him, with noiseless steps ¹ left his bed, by creeping on hands and knees ² got himself some distance off, and finding a rope which he had procured for the calamity of ending his life, he hung it from a nail fastened in the wall, and putting his neck in it breathed his last without the torments of a painful death. ³