3 At last he came to an iron door 4 That fast was locked, but key found not at all

fast > firmly

5 Amongst that bunch to open it withal;

withal > therewith

6 But in the same a little grate was pight,

grate > grating, grille pight > placed

7 Through which he sent his voice, and loud did call 8 With all his power, to weet if living wight

weet > find out wight > person

9 Were housed therewithin, whom he enlarge might.

enlarge > set free