Yonsei University Health System (YUHS) was founded in 1885 as the first modern medical institution in Korea by the American medical missionary, Dr. Horace N. Allen. It began as a small hospital under the name Kwanghyewon, which changed to Chejungwon and then Severance Hospital. As the hospital expanded over the years to include various colleges and research centers, the Yonsei University Health System was born (see Severance Hospital history for more information). YUHS has been the leader of medicine and is respected as the protector of Korean health. Furthermore, the roots of Christianity, modern medical education and medical care in Korea can all be linked to YUHS.