their > [his] wit > mental capacity, imagination; hence: heart
4 To let not other's honour be defaced,
defaced > disgraced
5 Of friend or foe, whoever it embased,
Of > By embased > degraded, humiliated
6 Nor arms to bear against the other's side: 7 In which accord the prince was also placed, 8 And with that golden chain of concord tied.
golden chain > [the golden chain; see 109.1]
9 So goodly all agreed; they forth yfere did ride.
goodly > courteously yfere > together
301.13