Final answer:
Franz Boas developed the four-field approach to anthropology and became the most prominent historical figure in the discipline.
Step-by-step explanation:
The most prominent historical figure in anthropology who developed the four-field approach was Franz Boas. He is credited with establishing the standards of field research that became the foundation of contemporary anthropological practices. Boas advocated for and published in all four fields of anthropology, namely biological anthropology, archaeology, cultural anthropology, and linguistic anthropology.