Sentence:  The extreme Puritans had an impact of no less import on the publishing activities of their enemies. In their attempt to halt the progress of forms of religion and religious opinion that had gone far beyond their own goals, several Presbyterian divines produced carefully assembled accounts of the heresies of their own times – they were the <WSD>Eusebiuses</WSD> of their day, and their works are now major sources for the history of the period. 
Meaning of the word marked with <WSD> tags:  One who is comparable to (Eusebius of Caesarea); an ecclesiastic historian.