Complex sentence: Robert was Chancellor of Brown University from 1998 to 2007, having previously been on the university's board of trustees since 1984, on its board of fellows since 1994, and on numerous committees including the committee on investment which he chaired from 1986 to 1997.
Split into simpler sentences: Robert was Chancellor of Brown University from 1998 to 2007, having previously been on the university's board of trustees since 1984, and on its board of fellows since 1994. He had also been on numerous committees, including the committee on investment which he chaired from 1986 to 1997.