This prince is incased in a magic armor, made by Merlin, and bears a shield fashioned from a single diamond, whose brightness is so dazzling that it has to be kept covered, so as not to blind all beholders.
After courteously greeting Una, the prince, hearing her tale of woe, volunteers to accompany her and free the Red Cross Knight.

When they reach the castle of Orgolio,--Spiritual Pride,--Arthur and his squire boldly summon the owner to come out and fight.

No answer is at first vouchsafed them, but after a blast from Arthur's magic bugle the gates burst open, and out of the stronghold rushes a seven-headed dragon, bearing on its back the witch Duessa.

This monster is closely followed by the giant Orgolio, who engages in fight with Prince Arthur, while the squire, Timias, directs his efforts against the seven-headed beast.

Although the prince and his attendant finally overcome these terrible foes, their triumph is due to the fact that in the midst of the fray Prince Arthur's shield is accidentally uncovered and its brightness quells both giant and beast.