Sentence:  At last he got his breath and answer'd, 'One, / One have I seen—that other, our liege lord, / The dread <WSD>Pendragon</WSD>, Britain's king of kings, / Of whom the people talk mysteriously, / He will be there—then were I stricken blind / That minute, I might say that I have seen.' 
Meaning of the word marked with <WSD> tags:  "Also capitalized as" '''(Pendragon)''': (title assumed by the ancient British chiefs when called to lead other chiefs): chief war leader, chieftain, dictator, despot or king.