The Roman legal system knew two forms of the death penalty: the summum supplicium was a more vindictive form involving burning alive, crucifixion, and exposure to wild animals, while the capite puniri involved a simple death by decapitation (Garnsey, Status, 124; A. Berger, Roman Law, 633). Further, two types of decollatio, “decapitation,” or capitis amputatio, “beheading,” were distinguished: that by the sword and that by the axe (Digest 48.19.8.1–2; Mommsen, Römisches Staatsrecht, 916–25). Provincial governors had the right to execute by sword only, not by the axe, javelin, club, or noose (Digest 48.19.8.1). Capital penalties were graded in accordance with degrees of extremity; the most extreme penalty was condemnation to the gallows, then burning alive, then beheading (Digest 48.19.28).

Roman legal practice exhibited a dual penalty system, which meant that punishments were meted out not only in accordance with the nature of the offense but also in accordance with the dignitas, “status,” of the offender (Garnsey, Status, 103–80; Gagé, Les classes, 283; Latte, RESup 7:1612; A. Berger, Roman Law, 633). Harsher punishments, including more violent forms of the death penalty, were inflicted on members of the lower classes (later designated humiliores), while the death penalty was rarely used for members of the upper classes (later called honestiores). For the upper classes various forms of exile or deportation were customarily used (see Comment on Rev 1:9). Decurions, for example, could not be executed (Digest 48.19.15; 48.19.27.1). Thus those who were beheaded with the axe referred to in [Rev. 20] v 4 in all probability belonged to the honestiores (the honestiores/humiliores distinction became more common in the second and third centuries, but the distinction in status that these terms describe did exist in the first century A.D. [Garnsey, Status, 221–76]).

 Revelation 17-22, Volume 52C (Word Biblical Commentary), Loc. 1086.