Complex sentence: The impetus for the institute's formation came from President of Columbia Dwight D. Eisenhower, Eisenhower had at first envisioned an endowed chair, or as he phrased it a "Chair for Peace", but the idea was then expanded into a full institute.
Split into simpler sentences: The impetus for the institute's formation came from President of Columbia Dwight D. Eisenhower. Eisenhower at first envisioned an endowed chair, or as he phrased it a "Chair for Peace", but the idea was then expanded into a full institute.