After several years of planning, the new Albert Einstein College of Medicine (AECOM) recruited its first class, of just 56 students, and began their instruction in the fall of 1955. This event took place in a not-yet-fully-outfitted Forchheimer building, which was then the only one of what later became a cluster of AECOM buildings. Across the street was the Bronx Municipal Hospital Center (BMHC, now Jacobi Medical Center, JMC), which was the original (and, for years, only) teaching hospital of the College. The evolution of the Department of Medicine at this new College, from its early stages – with 56 medical students, a small outstanding young faculty, one science building and one teaching hospital – to a world-renowned medical research and educational institution, with over 800 medical and doctoral students, numerous post-doctoral fellows and trainees, a large outstanding faculty, four major science buildings, and six major teaching hospital affiliates, is described.