Complex sentence: He accepted a commission in the Marine Corps in 1871 and served coninuously for 34 years, retiring as a Colonel in 1928 although he was promoted to Brigadier General on the retired list.
Split into simpler sentences: He accepted a commission in the Marine Corps in 1871. He served coninuously for 34 years, retiring as a Colonel in 1928 although he was promoted to Brigadier General on the retired list.