“It may seem strange to modern minds that for centuries it was a rule of our law that a man who killed another either by misadventure (per infortunium) or in reasonable self-defence (against an attack not itself felonious), although he did not commit a felony, must yet be held guilty of unlawful homicide and require the King’s pardon if he were to escape punishment, and even if granted pardon would still be liable to suffer forfeiture of his property; and that he was exposed to claims for compensation from the family of the deceased.” J.W. Cecil Turner, Kenny’s Outlines of Criminal Law 113 (16th ed. 1952).
per infortunium
per infortunium (p[schwa]r in-for-t[y]oo-nee-[schwa]m), adj. or adv. [Latin] By misadventure. • At common law, when one person killed another per infortunium, a conviction and royal pardon were necessary even when there was no fault. See homicide per infortunium under HOMICIDE.