Mezue ahịrịokwu na-esonụ: A mụrụ Ernst August Hagen na Königsberg, n'oge ahụ isi obodo nchịkwa nke East Prussia (na ihe fọrọ nke nta ka ọ bụrụ afọ iri mgbe
1806 mgbe eze si na Berlin gbapụ, ebe obibi nke ụlọ ikpe Prussian). Nna ya, Karl Gottfried Hagen (1749-1829) bụ ọkà mmụta ọgwụ a ma ama na onye na-ere ọgwụ n'obí eze.