The fateful blow which, in the Grail romances, created the Waste Land to be rendered barren. The Grail Quest was needed to heal the results of the Dolorous Stroke. The term is used to describe two separate events: the slaying of King Lambor (an early Grail King) by King Varlan, and the maiming of King Pellehan by Sir Balin the Savage. The former appears in the Vulgate Queste del Saint Graal, the latter is related in the Post-Vulgate Suite du Merlin, and both appear in Malory. In both versions of the Dolorous Stroke, a Grail King is attacked with a forbidden holy weapon.
In the Queste episode, King Lambor of Listenois, a Grail King, is at war with King Varlan of Wales. Varlan, forced to flee from Lambor, came across the Ship of Solomon, which contained the magnificent Sword with the Strange Hangings, intended for only the most pure knight. Disregarding the warning on the sheath, Varlan drew the sword and used it to slay King Lambor. This unholy blow turned both Listenois and Wales into the Waste Land, and Varlan was struck dead for his profanity when he returned the sword to the sheath.
In the Suite story, Sir Balin the Savage arrives at King Pellehan's court hunting Sir Garlon, an invisible marauder who was Pellehan's brother. Balin killed Garlon in Pellehan's hall. Pellehan, enraged, attacked Balin, shattering Balin's sword. Balin ran from room to room in Pellehan's castle, trying to find some other weapon, with Pellehan at his heels. In one room, he found a corpse in a bed and a long spear (the Bleeding Lance) resting on a nearby table. Balin did not know that the corpse was that of Joseph of Arimathea, and that the spear was the most holy of weapons - the very lance that pierced the side of Jesus Christ on the cross. Thus ignorant, Balin hefted the spear and struck Pellehan, which immediately caused Pellehan's castle to crumble and the land of Listenois to become the Waste Land. Pellehan's wound led to his identification as the Maimed King, and he remained ill until healed during the Grail Quest by Galahad.
A Grail king maimed in combat first appears in the earliest Grail story, Chrétien de Troyes's Perceval. Though not called the 'Dolorous Stroke', a blow has been delivered to the Fisher King, leaving him infirm. (The circumstances behind this wounding vary from text to text.) We also learn from Chrétien that the Bleeding Lance, found in the Fisher King's castle, will one day "destroy the realm of Logres". Also, in the first continuation of Chrétien's Perceval, Gawain is told by the Fisher King that the Grail Sword was used to strike a blow that laid the country of Logres to waste. (In Celtic mythology, similarly, King Bran is wounded in the foot by a poisoned spear, causing his land to suffer.) Thus, the idea of a weapon's blow, whether struck against the Fisher King or elsewhere, causing the destruction of a kingdom, appears in the earliest Grail legends, though the term 'Dolorous Stroke' is not used until later.
The Fisher King is not the only figure to be maimed through the thighs in the Grail legends. In the Vulgate Estoire del Saint Graal, the characters can barely walk from one place to another without being thrown to the ground by some heavenly blow. An angel shoves a lance through the thighs of Josephus (Josephe), son of Joseph of Arimathea, when he impiously abandons the conversion of some pagans to Christianity in order to save from death a group of pagans who refuse to convert. The angel later removes the lance and heals Josephus. In another episode, Nascien is injured by a flaming sword that appears out of nowhere when Nascien is too slow to alight from the holy Ship of Solomon (God was angry with Nascien because he had previously used the Sword with the Strange Hangings to kill a giant). Finally, Joseph of Arimathea himself is wounded in the thighs by a sword, which breaks, drips blood continually from the tip, and is thereafter called the Broken Sword.