Complex sentence: He earned his doctorate in history from the Soviet Academy of Sciences in 1990, and that same year moved to the United States to study at State University of New York at Binghamton under noted sociologist Immanuel Wallerstein.
Split into simpler sentences: He earned his doctorate in history from the Soviet Academy of Sciences in 1990. In the early 1990s, he moved to the United States to study at State University of New York at Binghamton under noted sociologist Immanuel Wallerstein.