Complex sentence: He subsequently taught at girls'schools in Trondhjem, Egersund, Haugesund and Røros for shorter periods before and after 1890, the year that he married Valborg Olsen, a photographer's daughter three years his junior.
Split into simpler sentences: He subsequently taught at girls'schools in Trondhjem, Egersund, Haugesund and Røros for shorter periods before and after 1890. In the latter year he married Valborg Olsen, a photographer's daughter three years his junior.