Sentence:  ...purſued his vnneighbourly purpoſe in ſuch ſort: that hee being the ſtronger perſwader, and ſhe (belike) <WSD>too</WSD> credulous in beleeuing or elſe ouer-feeble in reſiſting, from priuate imparlance, they fell to action; and continued their cloſe fight a long while together, vnſeene and vvithout ſuſpition, no doubt to their equall ioy and contentment. 
Meaning of the word marked with <WSD> tags:  To an excessive degree; over; more than enough.