Beat back and slew a southern king, through wrath

And puissance of Gwydion, whose path

Thence on, with love, he honored.

Now this Math

Was learned in wondrous witchcraft: as he willed,

He wrought the invisible visible, and filled

The sight with seeming shapes, which it believed

Realities, nor knew it was deceived.

For, at his word, the winds were wan with tents,

And armies rose of airy elements;