4 As if the rest some wicked hand did rend,
did rend > [had torn out]
5 Or the author himself could not at least attend
least > any rate attend > [turn his mind, turn his energies]
6 To finish it: that so untimely breach
breach > fracture, breaking-off
7 The prince himself half seems to offend, 8 Yet secret pleasure did offence impeach,
impeach > impede; prevent
9 And wonder of antiquity long stopped his speech.
of antiquity > at ancient times; at ancient records