1874: Dr. Andrew Taylor Still develops the osteopathic medical philosophy, pioneering the concept of "wellness" and recognizing the importance of treating illness within the context of the whole body.

1892: Dr. Still opens the first osteopathic medical school, the American School of Osteopathy, now known as A.T. Still University, in Kirksville, Missouri. The first class opened with 21 students, including six women.

1898: The second college of osteopathic medicine opens. AACOM is founded to support and assist the nation's osteopathic medical schools.

1921: Meta L. Christy, DO, graduates from the Philadelphia College of Infirmary and Osteopathy, now known as the Philadelphia College of Osteopathic Medicine, becoming the nation's first African American osteopathic physician.

1934: The Museum of Osteopathic Medicine opens in Kirksville, Missouri to preserve and promote osteopathic medicine's history and tenets to a global audience through collections and research.

1934: The first osteopathic licensing exam is administered in essay format. Margaret Barnes, DO, is awarded her certificate in 1936, becoming the first diplomate.

1947: Osteopathic residency programs are accredited and approved for DOs to continue their training.

1967: DOs are allowed to be commissioned into the military medical corps and are incorporated into the doctor draft.

1978: For the first time, more than 1,000 osteopathic medical students graduate from the United States’ nine osteopathic medical schools.

1978: The University of New England College of Osteopathic Medicine becomes Maine’s first medical school.

1993: Barbara Ross-Lee, DO, becomes the first African American woman to serve as dean of any U.S. medical school (DO or MD), the Ohio University Heritage College of Osteopathic Medicine.

1995-1998: The National Board of Osteopathic Medical Examiners (NBOME) develops the Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA) Levels 1 (first administered in 1998), 2 (1997) and 3 (1995).

2001: With Louisiana accepting the COMLEX-USA, DOs can be licensed in all 50 states and D.C. with their own licensure examination.

2008: The Class of 2008 is the first class required to take and pass the COMLEX-USA Levels 1, 2-Cognitive Evaluation and 2-Performance Evaluation to graduate.

2012: AACOM's Core Competency Liaison Group, consisting of representatives from AACOM, NBOME and every college of osteopathic medicine, publishes the “Osteopathic Core Competencies for Medical Students.”

2015: Osteopathic physicians gain full practice rights in 65 countries.

2017: The Idaho College of Osteopathic Medicine becomes Idaho’s first medical school.

2020: The osteopathic profession fully integrates into a single accreditation system for graduate medical education, allowing DOs and MDs to complete their residency training at the same programs.

2021: U.S. colleges of osteopathic medicine unanimously commit to a first-of-its-kind effort to address systemic inequity and increase medical student diversity.

2021: Record numbers of women apply (58 percent) and matriculate (53.7 percent) to osteopathic medical school.

2022: The Rocky Vista University Montana College of Osteopathic Medicine and the Touro College of Osteopathic Medicine-Montana become Montana’s first medical schools. Thirty-five states have osteopathic teaching locations.

2023: AACOM celebrates 125 years of leading and advocating for the full continuum of osteopathic medical education to improve the health of the public.

2024: On June 22, we celebrate 150 years of osteopathic medicine and honor Dr. Andrew Taylor Still's enduring legacy and mission to provide a more holistic approach to healthcare for all people.