A spetum was a pole weapon of Europe during the 13th century. It consisted of a long pole some 6–8 feet long on which was mounted a spear head with two projections at its base. Many variations of this design flourished over time; some feel that the ranseur is a variation of the spetum. Other names include chauve souris, corseca, corsèsque, korseke, runka, and rawcon. The spetum is usually distinguished from the ranseur and partisan by its "prongs" being single edged and used for slashing. The main blade was 12–14 inches long, and the side blades were only about half that length and were set at acute angles.
The design of a spetum is very efficient for combat. The main blade is long enough to destroy any significant organ in the human body with one quick thrust. The blunt backs of the side blades make the spetum extremely useful for a variety of uses such as tripping and knocking aside shields, but more importantly they provide far more strength to the sharpened side and points than is possible with any dual-edged construction. The sharpened front ends are useful for piercing or chopping in situations where precision is difficult. For example, one quick thrust of a spetum can easily remove the lower foreleg, ankle, and foot of an opponent with a side blade. Trying to do this with only a single spear point is incomparably more difficult. Similarly throat-level thrusts with a spetum can miss a direct hit by a huge distance and still completely impale the victim's neck.