Still he could not prevent his knights from setting out in quest of it, because they had solemnly vowed to do so.
"'Nay, lord, I heard the sound, I saw the light, But since I did not see the Holy Thing, I sware a vow to follow it till I saw.' "Then when he ask'd us, knight by knight, if any Had seen it, all their answers were as one: 'Nay, lord, and therefore have we sworn our vows.'" TENNYSON, _The Holy Grail_.
[Sidenote: Quest of the Holy Grail.] During this quest the knights traveled separately or in pairs all through the world, encountered many dangers, and in true mediaeval fashion defended damsels in distress, challenged knights, and covered themselves with scars and glory.

Some of the legends declare that Parzival alone saw the Holy Grail, while others aver that Lancelot saw it through a veil faintly.

The pure Galahad, having never sinned at all, and having spent years in prayer and fasting, finally beheld it just as his immaculate soul was borne to heaven by the angels.
The rest of the knights, realizing after many years' fruitless search that they were unworthy of the boon, finally returned to Camelot, where they were duly entertained by the queen.

While they were feasting at her table, one of their number, having partaken of a poisonous draught, fell lifeless to the ground.

As the incident had happened at the queen's side, some of her detractors accused her of the crime, and bade her confess, or prove her innocence by a judicial duel.