The acknowledged early adoption of placebo controls in drug trials by homeopaths is currently thought to have been derived from prior external attempts to discredit the system. This claim is reexamined in the light of a comprehensive literature search for 19th-century homeopathic therapeutic trials and provings using placebo. Single-blind placebo controls, still used today, are shown to have originated independently within homeopathy's own disciplinary matrix before the first external evaluations. They are the most likely source for later placebo-controlled crossover and parallel group experiments by homeopaths.