From a western viewpoint, music therapy in the 20th and 21st centuries (as of 2021), as an evidence-based, allied healthcare profession, grew out of the aftermath of World Wars I and II, when, particularly in the United Kingdom and United States, musicians would travel to hospitals and play music for soldiers suffering from war-related emotional and physical trauma. Using music to treat the mental and physical ailments of active duty military and veterans was not new. Its use was recorded during the US Civil War and Florence Nightingale used it a decade earlier in the Crimean War. Despite research data, observations by doctors and nurses, praise from patients, and willing musicians, it was difficult to vastly increase music therapy services or establish lasting music therapy education programs or organizations in the early 20th century. However, many of the music therapy leaders of this time period provided music therapy during WWI or to its veterans. These were pioneers in the field such as "Eva Vescelius", musician, author, 1903 founder of the short-lived National Therapeutic Society of New York and the 1913 "Music and Health" journal, and creator/teacher of a musicotherapy course; "Margaret Anderton", pianist, WWI music therapy provider for Canadian soldiers, a strong believer in training for music therapists, and 1919 Columbia University musicotherapy teacher; "Isa Maud Ilsen", a nurse and musician who was the American Red Cross Director of Hospital Music in WWI reconstruction hospitals, 1919 Columbia University musicotherapy teacher, 1926 founder of the National Association for Music in Hospitals, and author; and "Harriet Ayer Seymour", music therapist to WWI veterans, author, researcher, lecturer/teacher, founder of the "National Foundation for Music Therapy" in 1941, author of the first music therapy textbook published in the US. Several physicians also promoted music as a therapeutic agent during this time period.