Complex sentence: By 1917, as United States entered World War I, Annie Malone had become so successful that she founded and opened Poro College in St. Louis, the first educational institution in America dedicated to the study and teaching of black cosmetology.
Split into simpler sentences: By 1917, as United States entered World War I, Annie Malone had become so successful that she founded and opened Poro College in St. Louis. It was the first educational institution in America dedicated to the study and teaching of black cosmetology.