Complex sentence: Henley married Hannah (Anna) Johnson Boyle on 22 January 1878, Hanna (1855--1925) was the youngest daughter of Edward Boyle, a mechanical engineer from Edinburgh, and his wife, Mary Ann née Mackie.
Split into simpler sentences: Henley married Hannah (Anna) Johnson Boyle (1855--1925) on 22 January 1878. She was the youngest daughter of Edward Boyle, a mechanical engineer from Edinburgh, and his wife, Mary Ann née Mackie.