Christopher Columbus was searching for fame and fortune and planned to find his by finding a route to the "Indies" -- the source of the riches of the east, e.g., silk from China and spices from India. His proposal to King Ferdinand of Aragon and Queen Isabella of Castile (Aragon and Castile are now part of Spain) was to find the way to "the Indies" rather than to "India".
The term "Indies" meant to Europeans of Columbus' time not only India but what to us is East Asia and South Asia -- China, Japan, South-East Asia and India.
Columbus believed that if he sailed westwards from Europe into the Atlantic Ocean far enough he would reach Cipango (or Zipangu or Zipangri, and to us: Japan). This he had deduced from reading Marco Polo's account of his (Marco) travels in China and the orient.
Columbus had grossly underestimated the distance from Spain westwards to Japan but fortunately for him the Americas are located in the oceans (Atlantic & Pacific) between Europe and "the Indies" he sought. When he chanced upon the islands in the Caribbean he thought he had found "the Indies" and called the inhabitants "Indians" -- not because they were people of India but because they were people of "the Indies".
Author "Taierzhuang 1938 – Stalingrad 1942", see --
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