gan to > began to; did
5 Or heard abroad, of her champion true, 6 That in his armour bore a crosslet red.
in > [on] crosslet > small cross (term in heraldry)
7 "Ay me, dear dame!" quoth he, "well may I rue
Ay me > Ah me! Alas! (chiefly in northern dialect)
8 To tell the sad sight which my eyes have read:
read > seen
9 These eyes did see that knight both living and eke dead."
eke > also
106.37