This thesis examines how rebellion, usurpation and conspiracy to usurp imperial power (all crimes of high treason) were suppressed by the state during the Late Empire, with a particular focus on the years 397-411, during the reign of the western Emperor Honorius. The thesis identifies four themes common to the endgame of treason: 1. Sanctuary: Although this was frequently sought, it almost never worked for fugitive rebel leader or usurpers, as the right to asylum was continually and flagrantly violated 2. Treatment in captivity: physical abuse, torture and mutilation 3. Poena post mortem: this included decapitation and head-display 4. The process of damnatio memoriae enacted against rebels, usurpers and other state enemies Three individual cases are examined in the context of the four themes stated above: 1. The revolt of the comes Africae, Gildo, in 397-8 2. The alleged attempt at usurpation by the western magister, Stilicho, in 408 3. The western usurper Constantine III, in 407-11 The thesis examines the background to each of these three cases; how each individual was presented by the state, and how all three represented themselves and the varying circumstances of each of the three men's suppression at the hands of the state. Chapter one, Defining Rebels and Usurpers, examines what characteristics determined whether an individual was perceived as either a rebel or a usurper within the Roman world. Chapter two, The Endgame of Treason, examines the aforementioned phenomena common to the suppression of rebellion and usurpation during the fourth and early fifth-centuries: the seeking of sanctuary, ritual mutilation, especially of the right hand, before death or exile, poena post mortem, and the practice of damnatio memoriae. Chapter three, The Eagle and the Snake; Gildo's revolt, 397-8, deals with the revolt of the comes Africae, Gildo, in 397-8. Chapter four, Shared Fates; Stilicho, Eucherius and Serena, 408, concerns the coup which toppled the comes et magister militum, Stilicho, in 408. Chapter five, The Usurpation of Flavius Claudius Constantinus, 407-11, deals with the usurper Constantine III, his numismatic self-representation, his dynastic propaganda, and his eventual defeat and beheading. The thesis asks this key question; did the form of punishment, both before and after death or exile, of a person charged (reus/rei) with high treason (crimen maiestatis) differ in relation to whether they were categorised as a rebel or a usurper? It was common for usurper's heads to be exhibited on the walls of Roman cities post-defeat. Michael McCormick contends that the ritualised display of usurpers' heads was the state's means of convincing rebellious troops to submit, once they had seen their former leaders' decapitated heads upon spikes. The present thesis expands upon this by suggesting that it was only usurpers whose heads were displayed, as they were the only ones who had minted coins and were thus widely recognised. Rebels, on the other hand, tended not to receive the same treatment, though they did endure the other accompanying torments, torture and humiliation if taken alive, and poena post mortem once deceased.