Complex sentence: As a young second lieutenant, he joined the 110th Fusilier Regiment during World War I. After World War I, he joined the Freikorps and fought in the Baltic region during 1919.
Split into simpler sentences: As a young second lieutenant, he joined the 110th Fusilier Regiment during WWI. After WWI, he joined the Freikorps and fought in the Baltic region during 1919.