Complex sentence: In 1887 he was elected to the Senate as a Democrat and served from March 4 1887 until his death, aged 70, in Washington, D.C. in 1891.
Split into simpler sentences: In 1887 he was elected to the Senate as a Democrat and served from March 4 1887 until his death. He died, aged 70, in Washington, D.C. in 1891.