Complex sentence: Between 1996 and 1998 he served as head of the Mossad, and between 1999 and 2001 he served as Prime Minister Ehud Barak's Chief Of Staff and security advisor.
Split into simpler sentences: Between 1996 and 1998 he served as head of the Mossad. Between 1999 and 2001 he served as Prime Minister Ehud Barak's Chief Of Staff and security advisor.