Giant cell arteritis and polymyalgia rheumatica were described separately more than 100 years ago. However, the original reports of both conditions were neglected for many years. After the article by Horton et al on giant cell arteritis in the 1930s and studies published by others in the 1940s, giant cell arteritis began to be recognized as a specific disease. In the 1950s and 1960s, many of the numerous presentations and complications of giant cell arteritis were recorded. In a somewhat similar fashion, physicians became cognizant of polymyalgia rheumatica only after several independent descriptions in the 1940s and 1950s. The rapid response of both syndromes to glucocorticoid therapy was discovered shortly after cortisone's effect on rheumatoid arthritis was described. The origin of the proximal aching and stiffness in polymyalgia rheumatica was more difficult to understand. The relatively minor findings in the joints on physical examination seemed insufficient to account for the severe discomfort. As the link between polymyalgia rheumatica and giant cell arteritis became apparent, some thought the aching in polymyalgia rheumatica was related to vasculitis. The debate about whether proximal synovitis or vasculitis was the cause of the symptoms continued after 1970. Although the reason these 2 conditions were associated was not considered by 1970, the establishment of the syndromes as clinically linked entities provided the groundwork for further progress in the next decades.