He believed he had sailed all the way around the world and didn't know that North America existed. However, he didn't really think he had reached Asia. He thought he had reached the East Indies, an island chain containing Indonesia.
He made mistake in estimating size of earth..He calculated size more than half..Hence he thought he reach Asia without knowing he discovered a new American Land. ;
Columbus believed he reached Asia due to significant underestimations of the Earth's size and unawareness of the Americas. He thought he was only about 3,000 miles from Asia when in fact, the distance was much greater. His continued assertions and naming of the indigenous peoples contributed to this misunderstanding throughout his life.
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