Colonial India is the part of the South of Asia which was under the jurisdiction of European colonial powers, through trade and conquest. The first European power to arrive in the region was the Macedonian army of Alexander the Great in present-day Eastern Afghanistan and Western Pakistan in 327–326 BCE. The satraps he established in the north west of the region quickly crumbled after he left. Later, trade was carried between Indian states and the Roman Empire by Roman sailors who reached India via the Red Sea and Arabian Sea, but the Romans never sought trading settlements or territory in India. The spice trade between India and Europe was one of the main types of trade in the world economy and was the main catalyst for the period of European exploration. The search for the wealth and prosperity of India led to the accidental "discovery" of the Americas by Christopher Columbus in 1492. Only a few years later, near the end of the 15th century,  Portuguese sailor Vasco da Gama became the first European to re-establish direct trade links with India since Roman times by being the first to arrive by circumnavigating Africa (1497–1499). Having arrived in Calicut, which by then was one of the major trading ports of the eastern world, he obtained permission to trade in the city from Saamoothiri Rajah.