In a Sidonian sarcophagus, from the Late Antique/early Christian period, skeletal remains of two persons were found. One of them, male, 30-50 years old, was found almost completely ankylosed, with highly osteoporotic bones and prominent erosion of joint surfaces. We diagnosed rheumatoid arthritis based on the eroded odontoid process, mandibular condyles, distal humerus, proximal and distal ulna, as well ankylosed hand and foot bones. Despite the fact that ankyloses of vertebrae and sacroiliac joint could point towards ankylosing spondylitis, the lack of typical vertebral ankyloses and new bone formation led to exclusion. In a practical sense, due to the advanced stage of the disease, the man was fixed in the supine position, on the left, with his head turned to the right. Apparently, he could not move and had problems with chewing and breathing. But, the high standard of provided healthcare probably enabled him to survive in advanced stages of the disease. This case shed light on the antiquity of the disease, its medical, and social context and provided the example of most extreme osteological changes reported in the paleopathological and medical literature.