Sentence:  [T]he whole intellectual <WSD>battle</WSD> that had at its centre the best poem of the best poet of that day, and had the English Revolution among issues of the strife, was quickening the energies within young Foe's ["i.e.", Daniel Defoe's] mind when his age was twenty. 
Meaning of the word marked with <WSD> tags:  A contest, a struggle.