Galahad (ˈɡæləhæd), sometimes referred to as Galeas (ɡəˈliːəs) or Galath (ˈɡæləθ), among other versions of his name, is a knight of King Arthur's Round Table and one of the three achievers of the Holy Grail in Arthurian legend. He is the illegitimate son of Sir Lancelot du Lac and Lady Elaine of Corbenic and is renowned for his gallantry and purity as the most perfect of all knights. Emerging quite late in the medieval Arthurian tradition, Sir Galahad first appears in the Lancelot–Grail cycle, and his story is taken up in later works, such as the Post-Vulgate Cycle, and Sir Thomas Malory's Le Morte d'Arthur.
The story of Galahad and his quest for the Holy Grail is a relatively late addition to the Arthurian legend. Galahad does not feature in any romance by Chrétien de Troyes, or in Robert de Boron's Grail stories, or in any of the continuations of Chrétien's story of the mysterious castle of the Fisher King. He first appears in a 13th-century Old French Arthurian epic, the interconnected set of romances known as the Vulgate Cycle. His name could have been derived from the Welsh name Gwalchaved, meaning "Falcon of Summer".
The original conception of Galahad, whose adult exploits are first recounted in the fourth book of the Vulgate Cycle, may have come from the mystical Cistercian Order. According to some interpreters, the philosophical inspiration of the celibate, otherworldly character of the monastic knight Galahad came from this monastic order set up by St. Bernard of Clairvaux. The Cistercian-Bernardine concept of Catholic warrior asceticism that so distinguishes the character of Galahad also informs St. Bernard's projection of ideal chivalry in his work on the Knights Templar, the Liber ad milites templi de laude novae militiae. Significantly, in the narratives, Galahad is associated with a white shield with a vermilion cross, the very same emblem given to the Knights Templar by Pope Eugene III.
The circumstances surrounding Galahad's conception derive from the earlier parts of Grail prose cycles.