Complex sentence: In 1962, he was appointed commander of the III Corps, which oversaw the region surrounding the capital Saigon, as Diem regarded him as one of his most loyal officers.
Split into simpler sentences: In 1962, Dinh was appointed commander of the III Corps, which oversaw the region surrounding the capital Saigon. He was given the post as Diem regarded him as one of his most loyal officers.