The opera opens in the forest, where Gurnemanz, an old servant of Amfortas, guardian of the Holy Grail, is lying asleep with two squires. Suddenly, reveille sounds from the top of Mount Salvat, the sacred hill upon which the temple stands. Gurnemanz, springing to his feet, rouses the squires, and bids them prepare the bath for their ailing master, who will soon appear as is his daily custom.
This Amfortas, whose coming they momentarily expect, is the son of Titurel, the founder of the temple erected on Mount Salvat for the reception of the Holy Grail, a vessel in which Joseph of Arimathea caught a few drops of blood from the dying Redeemer's side, after it had served as chalice during the Last Supper. Titurel, feeling too old to continue his office as guardian of the Grail, appointed Amfortas as his successor, giving him the sacred lance which pierced the Saviour's side, and told him that none could resist him as long as he wielded it and kept himself perfectly pure.
During many years Amfortas led a stainless life, defending the Holy Grail from every foe, performing all his sacred offices with exemplary piety, and teaching the Knights of the Grail to fight for the right, and rescue the feeble and oppressed. He also sent out messengers to all parts of the world to right the wrong, whenever called upon to do so, by the words which suddenly appeared and glowed like fire around the edge of the mystic vase. All the knights who served the Holy Grail were not only fed with celestial viands by its power alone, but were endowed with resistless might, which assured their victory everywhere as long as they remained unknown. They had moreover the privilege of recovering, as if by magic, from every wound. Of course, many knights were desirous of being admitted into the temple, but none except those whose lives were pure and whose purposes lofty were ever accepted. When Klingsor, the magician, attempted to enter, therefore, he was repulsed. In his anger he established himself upon the other side of the mountain, where, summoning all the arts of magic to his aid, he called up delusions of every kind. Thus he beguiled many of the knights in search of the Holy Grail, caught them in his toils and led them on to sin, until they were unfit for the holy life to which they had once aspired.
Amfortas, hearing of this, and too confident in his own strength, sallied forth one day, armed with the sacred lance, determined to destroy Klingsor, and put an end to his magic. But alas! he had no sooner entered the magician's garden, where roamed a host of lovely maidens trained to lure all men to sin, than he yielded to the blandishments of the fairest among them. Carelessly flinging his sacred lance aside, he gave himself up to the delights of passion. Such was his bewitched condition that he never even noticed the stealthy approach of the magician, who seized the lance and thrust it into his side. This deep wound, which had refused to heal ever since, caused him incessant tortures, which were increased rather than diminished whenever he uncovered the Holy Grail.
Although no remedy could allay this torture, the Holy Grail decreed that it should be stilled by a guileless fool, who, enlightened by pity, would find the only cure. But, as he tarried, many knights travelled all over the world in search of simples, and Kundry, a wild, witch-like woman, also sought in vain to relieve him.
While the squires, in obedience to Gurnemanz's orders, prepare the bath, Kundry comes riding wildly on the scene. In breathless haste she thrusts a curious little flask into Gurnemanz's hand, telling him it is a precious balsam she has brought from a great distance to alleviate Amfortas's suffering. She is so exhausted by her long ride that she flings herself upon the ground, where she remains while a little procession comes down the hill. It is composed of knights bearing the wounded Amfortas, and they set the litter down for a moment, as the king gives vent to heart-rending groans. To soothe him, his attendants remind him that there are many more remedies to try, and Gurnemanz adds that, failing all others, they can always rely upon the promise of the Holy Grail, and await the coming of the guileless fool. When Amfortas learns that Kundry has made another attempt to help him, he thanks her kindly, but his gentle words only seem to increase her distress, for she writhes uneasily on the ground and refuses all thanks.
When the king and his bearers have gone down the hill, and have passed out of sight, the squires begin chaffing poor Kundry. She gazes upon them with the wild eyes of an animal at bay, until Gurnemanz comes to her rescue, and chides the youths. He tells them that although she may once have been, as they declare, under a curse, she has repented of her sins, and serves the Holy Grail with a humility and singleness of purpose which they would do well to imitate rather than deride.
In answer to their questions, he then goes on to describe how Amfortas received the grievous wound which causes him such intolerable pain, and lost the sacred spear, which only enhances Klingsor's power for evil, and which none but a stainless knight can ever recover. Their quiet conversation is brusquely interrupted by the heavy fall of a swan, which lies dead at their feet. This arouses their keenest indignation, for the rules of the order forbid any deed of violence within sight or hearing of the sacred edifice containing the Holy Grail. Gazing around in search of the culprit, they soon behold the youth Parsifal, clad in the rough and motley garments of a fool, and when Gurnemanz angrily reproves him, and questions him concerning his name and origin, he is amazed by the ignorance the lad displays.
By the help of Kundry, however, who, having travelled everywhere, knows everything, Gurnemanz finally ascertains that the youth is a descendant of the royal family, his father, Gamuret, having died when he was born. His mother, Herzeloide (Heart's Affliction), has brought him up in utter solitude and ignorance, to prevent his becoming a knight and leave her perchance to fall in battle:—
‘Bereft of father his mother bore him.
For in battle perished Gamuret:
From like untimely hero's death
To save her offspring, strange to arms
She reared him a witless fool in deserts.’