Complex sentence: He served as president for the first time from 3 October 1963 until 7 June 1971, taking office when he seized power in the 1963 Honduran coup d'état, 10 days before presidential elections were due.
Split into simpler sentences: He served as president for the first time from 3 October 1963 until 7 June 1971. He took office when he seized power in a military coup 10 days before presidential elections were due.