Why did Columbus call the islands he discovered, the Indies?

Why did Columbus call the islands he discovered, the Indies?

Christopher Columbus was an Italian sea captain who served Spain. In 1492, in a ship not much bigger than a modern racing yacht, he sailed across the Atlantic, a journey that many were terrified to make. Sailors never sailed out of sight of land. Columbus wanted to discover a new trade route to the riches of the Far East. He knew that the world was round and by sailing towards the West, he could find this route.
He did not know that the large continents of North and South America lay in his way, and his calculations of how big the earth was, proved wrong. When he sighted land after ten weeks, Columbus thought he had reached the outskirts of Asia. He believed that he had discovered the Indies, and named them so. He made three more voyages to the West Indies, still believing them to be part of Asia.
Spain, however showed great enthusiasm towards these discoveries and took up explorations and colonization efforts on a large scale