2 Dispersed the shadows of the misty night, 3 And Titan, playing on the eastern streams, 4 Gan clear the dewy air with springing light,
Gan > Did; began to springing > rising, growing; dawning
5 Sir Guyon, mindful of his vow plight,
vow plight > [plighted vow]
6 Uprose from drowsy couch, and himself addressed 7 To the journey which he had behight:
behight > promised (to Gloriana)
8 His puissant arms about his noble breast,
puissant > mighty arms > armour (shares the vb. "bound" with the "shield" in line 9)
9 And many-folded shield he bound about his wrist.
many-folded > (Consisting of many layers, seven in fact: see 205.6:3, 208.32:5. Guyon carries the classical seven-layered shield as borne by Ajax at Iliad 7.220 (imitated by Virgil at Aen. 12.925). In Homer the layers are of bull's-hide)