Complex sentence: On 23 October 1955, Diệm toppled Bảo Đại in a fraudulent referendum orchestrated by Nhu, and declared himself President of the newly proclaimed Republic of Vietnam three days later.
Split into simpler sentences: On 23 October 1955, Diệm toppled Bảo Đại in a fraud-ridden referendum orchestrated by Nhu. Diệm declared himself President of the newly proclaimed Republic of Vietnam three days later.