The rulers of Spain sought a shorter route to the East Indies primarily to gain direct access to lucrative trade in spices, silk, and other valuable goods, which were highly sought after in Europe. By finding a more efficient route, they aimed to reduce dependence on intermediaries and lower transportation costs, thereby increasing profits. Additionally, establishing a quicker passage would enhance Spain's competitive edge over rival powers, particularly Portugal, in the race for colonial expansion and trade dominance.
To get silk and spices
Simply for the trade and the money it would bring.
To reduce the cost of trade, and shorten the time to move goods from one place to another.
Spain did not set out to establish a new world. They were looking for a shorter route to a destination they already knew about. They tripped over the "New World" by mistake. They thought they were in the East Indies.
1492
He could have used either of the routes you suggest. However Columbus was on a journey of exploration to see if there was a shorter faster route to the Indies by sailing to the west.
He probably explained his theory that the world was a sphere and that it should be a shorter trip to the East Indies (Southeast Asia). if he went west around the globe, than the current route. The route at that time was south around the tip of Africa, up the east coast of Africa, and across the Indian Ocean. He would have explained the commercial advantages to Spain if they had a shorter trip than the competition. Then he probably asked for the financing.
Christopher Columbus was searching for a Northwest Passage, or a direct water route to the Indies from Spain.
Christopher Columbus did not discover India. India was known centuries before his birth. I don't believe he ever got to India. He was trying to find a shorter route to the Indies when he tripped across the Americas.
Christopher Columbus was sent by Spain to find an all-water trade route to the West Indies. In 1492, he embarked on his first voyage across the Atlantic Ocean, aiming to reach Asia by sailing west. Instead, he encountered the islands of the Caribbean, which he believed were part of the East Indies. His expeditions ultimately led to the European awareness of the Americas.
Queen Isabella chartered Columbus to find a route westward from Spain to China and the Indies.
the Spanish royals financed Colombus' voyage because they were hoping we would discover a faster route to the Indies.