shields nullified projectile weapons and nonnuclear explosives Hence the Great Houses were obliged to resort to treachery and profession al assassination in order to carry on their perennial vendettas All Great Houses customarily hired a master assassin-usually one with Mentat training m logic and the traditional Mentat dis trust of emotion-to oversee me defenses of the family household, supervise the house's corps of assassins, and in some cases to command units of troops or mercenaries Their function was therefore both offensive and defensive Consequently a "war of assassins ' between two great houses often took on die appearance of a Cheops game between two grand masters However, some great barons or dukes, fake Duke Leto Atreides, although relying on the advice of their chief assassin, may be said to have managed-or mismanaged-their own campaigns The first recorded instance of a war of assassins is the conflict between House Pardee and House Harkonnen in 3367-3375, a conflict which virtually obliterated House Pardee This war involved an extensive use of poison, but it was climaxed by the famous Lasgun Massacre when Harkonnen mercenaries ambushed Duke Ira Pardee and his family at their hunting lodge on the planet of New Salem Various stones attribute this victory to the defection of the steward of their rural estate a jealous functionary who was easily bribed Undermining the loyalty of the retain ers of another house was a specialty at which House Harkonnen seems to have excelled, according to the reputation of the house among others in the Old Impenum An outright war of assassins always required, under the Great Convention, a formal declaration of intent to be filed with the Imperial Court, the offices of the Guild, and the Secretary of the Landsraad Imperial judges were appointed to monitor the conflict and particularly to observe an> instances where innocent bystanders might be harmed Such actions did not always ensure the safety of noncombatants nor a fair treatment of the two houbeb involved, for the emperor was seldom completely disinterested in the conflict But the observation made the feuding houses wary of harming or even involving outsiders Numerous famous wars of assassins occurred in Impenal history, often altering the balance of power among the Great Houses of the Landsraad For instance House Galloway was powerful in the third millennium, but was nearly destroyed in its war of assassins with House Albonite Some other well known wars of assassins were the Stemhauser Boudreau feud (8193 8195) and the Choi-Dwyer-Ferguson war (8787-8843), a three cornered bloodbath from which each house emerged weakened This latter conflict was unusually bitter and ended only when the emperor himself interceded with the families in conflict The important wars of assassins dominated political history of the last century of the pre-Atreides Impenum The first of these was the feud of House Montani of Grumman with House Ginaz, the latter an