The now-common English label Dhyani Buddha, used loosely for Ratnasambhava and the other four buddhas of the mandala scheme, traces back to a specific historical figure: Brian Houghton Hodgson, a British colonial official who served for many years in the early nineteenth century as the East India Company's Resident in Kathmandu, and who used his diplomatic posting to undertake one of the earliest serious Western scholarly investigations of Newar Buddhism, the distinctive form of Mahayana and Vajrayana Buddhism preserved among the Newar people of the Kathmandu Valley.
Hodgson collected an enormous number of Sanskrit and Newari Buddhist manuscripts, many of which he sent to libraries and scholars in Europe, effectively supplying much of the primary textual material on which the earliest generation of Western Buddhology was built, and in the process he introduced terminology, including Dhyani Buddha, to categorize concepts that did not map neatly onto existing European religious vocabulary.
Subsequent scholarship has noted that Hodgson's terminology, however useful as an entry point, does not always correspond precisely to how these figures are named within the traditions themselves, and specialists today generally prefer more precise, tradition-internal terms, the Five Tathagatas or the Sanskrit and Tibetan names, over Hodgson's nineteenth century coinage. That the most familiar English term for a figure as central to tantric visualization as Ratnasambhava originates not from any Buddhist source but from a British diplomat's attempt to translate an unfamiliar system for a European audience is a reminder of how much modern vocabulary for Asian religious traditions was shaped by the sometimes idiosyncratic choices of early colonial-era scholars.