This spy, meeting Erminia there, induces her not only to reveal all the Egyptians' plans (including a plot to slay Godfrey), but to go back with him.

While they journey along together to rejoin the Christian forces, Erminia relates her adventures, saying that while she was playing shepherdess, some freebooters seized her and carried her to the Egyptian camp, where she was placed under Armida's protection.

Her story is just finished when they perceive what appears to be a lifeless warrior.

By the red cross on his armor the spy recognizes a Christian, and further investigation enables him to identify Tancred.
Erminia--who has owned she loves him--now takes possession of him, binds up his wounds with her hair (!), and vows she will nurse him back to health.
_Canto XX._ Warned by his spy that the Egyptians mean to send sundry of their number to mix, during the battle, with his body-guard and kill him, Godfrey changes the ensigns of his men, and thus discovers the conspirators, who are promptly put to death.

Seeing the Egyptian army advance, Godfrey, in a stirring speech, urges his men to do their best for the Holy Sepulchre, and thereby stimulates them to fight so bravely that many of them lose their lives.