Complex sentence: He engaged in the real estate business in Chicago, Illinois from 1905 to 1917 served in the United States Navy from 1917 through 1919, being honorably discharged with the rank of senior lieutenant.
Split into simpler sentences: He engaged in the real estate business in Chicago, Illinois from 1905 to 1917. He served in the United States Navy 1917-1919 and was honorably discharged with the rank of senior lieutenant.