Complex sentence: Consul James H. Keeley served as principal officer at the Consulate until the outbreak of World War I in 1939, and one of his sons, Robert V. Keeley, would later become U.S. ambassador in the embassy at Athens.
Split into simpler sentences: Consul James H. Keeley served as principal officer at the Consulate until the outbreak of World War I in 1939. One of his sons, Robert V. Keeley, would later become U.S. ambassador in the embassy at Athens.