goodly > beautifully, excellently edified > built

5 And placed for pleasure nigh that forest side: 6 But fair before the gate a spacious plain, 7 Mantled with green, itself did spread wide, 8 On which she saw six knights, that did deraign

deraign > {Challenge; fight in order to settle a dispute}

9 Fierce battle against one, with cruel might and main.

cruel > savage; cruel main > force, strength

301.21

Mainly they all attonce vpon him laid,
2 And sore beset on euery side around,
That nigh he breathlesse grew, yet nought dismaid,
4 Ne euer to them yielded foot of ground
All had he lost much bloud through many a wound,
6 But stoutly dealt his blowes, and euery way
To which he turned in his wrathfull stound,
8 Made them recoile, and fly from dred decay,
That none of all the sixe before, him durst assay.

1 Mainly they all at once upon him laid,

Mainly > Powerfully

2 And sore beset on every side around, 3 That nigh he breathless grew, yet naught dismayed,