Religious comparison needed a geography if it was to explain how distant peoples had become connected. Carl Ritter (1779–1859) supplied one in his 1820 study of the peoples who preceded the earliest Greek histories. He looked to the region of the upper Indus and the Oxus, the river now called the Amu Darya, for an early centre from which peoples and teachings had moved in several directions. His interest in the Caucasus gave particular attention to their passage toward the Black Sea and Europe.
This was not a single westward journey beginning on India’s southern coast. Ritter brought together different routes of trade and migration. His Indian Colchi, associated with the pearl fisheries near the southern tip of India, entered a maritime connection toward the Persian Gulf and onward through western Asia toward Armenia and the Black Sea. Northern routes and movements farther east belonged to the wider account. Similar names in distant places helped him connect its parts, sometimes more confidently than the evidence allowed.
The routes made the comparison more persuasive because they gave readers places to follow. Mountains, rivers, and trading connections supplied a physical setting for an early religious history. Yet the passage of a trader along a known route did not establish that every doctrine Ritter associated with it had made the same journey. His geography and his proposed religious ancestry supported each other without always resting on evidence of equal strength.
Religious names served a comparable purpose. Ritter associated the Indian Budha, linked with Mercury and Wednesday, with the northern Odin or Woden, whose name also survived in the weekday. He placed such comparisons within a reconstructed early religion that should not be confused with Buddhism as historians now identify it. The proposed agreement among gods helped explain the migrations, while the migrations made the agreement seem historically possible.
Ritter’s learning gave a speculative religious ancestry the detail of a geographical investigation. Its attraction to other scholars is visible in a concrete American response. Charles Anthon (1797–1867) announced plans for a book on the connections between eastern and western religions founded on Ritter’s work. The proposed volume never appeared. Its announcement nevertheless placed Ritter’s account before the American students and readers for whom Anthon was preparing his reference books.