Complex sentence: His large-scale work, "A Sunday Afternoon on the Island of La Grande Jatte" (1884--1886), altered the direction of modern art by initiating Neo-impressionism, and is one of the icons of late 19th-century painting.
Split into simpler sentences: His large-scale work "A Sunday Afternoon on the Island of La Grande Jatte" (1884--1886) altered the direction of modern art by initiating Neo-impressionism. It is one of the icons of late 19th-century painting.