Great God! I'd rather be a Pagan

With the cry 'Great God!', the poem turns. The poet says he would rather be a Pagan, brought up in an old, outdated faith ('a creed outworn'), than live as people do now.

Then, standing on a pleasant meadow (a 'lea'), he might glimpse sights that would make him less sad ('less forlorn').

He might see Proteus, the shape-changing sea god of Greek myth, rising from the sea; or hear Triton, another sea god, blowing his wreathed shell horn.

The poet is not really asking to change his religion. He means that the ancient Greeks, who saw gods in the sea and the wind, at least felt Nature as something alive, which modern people no longer do.

These last six lines are the sestet. They rhyme CDCDCD. An octave plus a sestet makes a Petrarchan (Italian) sonnet. Shakespeare's sonnet, by contrast, has three quatrains and a couplet.