Complex sentence: He served in the Navy from 1872 until his retirement in October 1918, by which time he had risen to the rank of Admiral, and the post of State Secretary for the "Reichsmarineamt" (Imperial Navy Office).
Split into simpler sentences: He served in the Navy from 1872 until his retirement in October 1918. By the time he had retired, Capelle had risen to the rank of Admiral, and had served in the post of State Secretary for the "Reichsmarineamt" (Imperial Navy Office).