Complex sentence: He held many roles within the party, including chairing the Liberal Party Assembly committee, responsible for organising the party's conferences, and was author of a number of influential pamphlets championing liberal philosophy and the principles of community politics.
Split into simpler sentences: He held many roles within the party, including the chair of the Liberal Party Assembly committee responsible for organising the party's conferences. He also authored a number of influential pamphlets championing liberal philosophy and the principles of community politics.