Complex sentence: He is said to have been almost continuously employed during the next twenty years of peace and war, but the details of his service cannot now be satisfactorily traced; those given by Charnock are not entirely trustworthy; some of them appear very doubtful.
Split into simpler sentences: He is said to have been almost continuously employed during the next twenty years of peace and war, but the details of his service cannot now be satisfactorily traced. Those given by Charnock are not entirely trustworthy and some of them appear very doubtful.