The recognition of IgG4-RD as a unique immune-mediated disease dates back only to 2003. Before then, the medical literature was rife with parallel reports of patients with major salivary gland enlargement; inflammation in the pancreas and bile ducts; and fibrosis in diverse organs, all believed to be distinct and unrelated conditions. Patients' conditions were labelled incorrectly or not recognized at all, often undergoing unnecessary tests and enduring treatments that they did not need, were often harmful, or both. Since the turn of the century, progress on the understanding of IgG4-RD through clinical investigation, clinical trials, translational research, and guidelines development has been impressive. We invite you to read some of the milestones along the way to the present, and anticipate the future.