Complex sentence: A native of Milan, Sonzogno was the son of a businessman who owned a printing plant and bookstore; when he inherited the business upon his father's death he set about turning it into a publishing house, Casa Sonzogno, which opened in 1874.
Split into simpler sentences: A native of Milan, Sonzogno was the son of a businessman who owned a printing plant and bookstore. When he inherited the business upon his father's death he set about turning it into a publishing house, Casa Sonzogno, which opened in 1874.