Complex sentence: He was diplomatic correspondent at "The New York Times" from 1973 to 1977; later, between 1981 and 1993, he was in turn national security correspondent, deputy editorial page editor, editor of the Op-Ed Page, and columnist.
Split into simpler sentences: He was diplomatic correspondent at "The New York Times" from 1973 to 1977. He returned to the "Times" in 1981; from then until 1993, he was in turn its national security correspondent, deputy editorial page editor, editor of the Op-Ed Page, and columnist.