Theodor Fliedner (1800–1864) was a German Protestant pastor and social reformer. In 1836, together with his wife Friederike, he founded the Kaiserswerth Deaconess Institute, combining nursing education, hospital practice, and religious service. Its model helped professionalise nursing, spread internationally, and influenced Florence Nightingale.

Florence Nightingale (1820–1910) founded modern nursing in Great Britain, transforming it from a disreputable occupation into a respected profession. Despite fierce family opposition, Nightingale persisted, eventually training at the Nursing School of Protestant Deaconesses in Kaiserswerth, Germany, in 1851. During the Crimean War, she led 38 nurses to Scutari, where she implemented sanitation measures that drastically reduced the mortality rate from 42% to 2%. Known as "The Lady with the Lamp," she also pioneered medical statistics, creating polar area diagrams to visualise preventable deaths. In 1860, she established the first secular nursing school at St Thomas' Hospital, London. Her legacy endures through International Nurses Day, celebrated on her birthday, and her foundational text Notes on Nursing.