The sabre or saber (see spelling differences) is a type of backsword, usually with a curved, single-edged blade and a rather large hand guard, covering the knuckles of the hand as well as the thumb and forefinger. Ultimately based on a medieval type of single-edged weapon and European backsword, the sabre was adopted as the weapon of heavy cavalry in Early Modern warfare. Although sabres are typically thought of as curved-bladed slashing weapons, those used by the heavy cavalry of the 17th to 19th centuries often had straight and even double-edged blades more suitable for thrusting.