1 It falls me here to write of chastity,

falls > befalls

2 That fairest virtue, far above the rest; 3 For which what needs me fetch from Faery

needs me > do I need to; need do I have to

4 Foreign examples, it to have expressed?

expressed > portrayed, represented; represented symbolically

5 Sith it is shrined in my sovereign's breast,

Sith > Since shrined > enclosed, enshrined

6 And formed so lively in each perfect part,

lively > {Livelily, in a lifelike manner}