4 The antique rolls, which there lie hidden still,

antique > ancient

5 Of Faery knights and fairest Tanaquil,

Faery > {An archaic variant of "fairy", used by Spenser to denote
the imaginary land, analogous to Britain, where his poem is set}
Tanaquil > (Caia Tanaquil, wife of Tarquinius Priscus, 5th King of
Rome (- 577 BC); an exemplary queen, taken as a type for the
Faery Queen. See 210.76)

6 Whom that most noble Briton prince so long

Briton prince > (Prince Arthur. For the origin of Arthur's quest for the Faery Queen, see 109.8-15)

7 Sought through the world, and suffered so much ill,

suffered > [for whom he suffered] ill > evil, distress

8 That I must rue his undeserved wrong: 9 O, help you my weak wit, and sharpen my dull tongue!

help you my > [help my; "you" intensifies the imperative mood] wit > wit; mind dull > dull, lacklustre; blunt