Called the Queen of the Arabian Sea, Kochi was an important spice trading centre on the west coast of India from the 14th century onward, and maintained a trade network with Arab merchants from the pre-Islamic era. Occupied by the Portuguese in 1503, Kochi was the first of the European colonies in colonial India. It remained the main seat of Portuguese India until 1530, when Goa was chosen instead. The city was later occupied by the Dutch and the British, with the Kingdom of Cochin becoming a princely state. Kochi ranks first in the total number of international and domestic tourist arrivals in Kerala. The city was ranked the sixth best tourist destination in India according to a survey conducted by the Nielsen Company on behalf of the Outlook Traveller magazine. Kochi was one of the 28 Indian cities among the emerging 440 global cities that will contribute 50% of the world GDP by the year 2025, in a 2011 study done by the McKinsey Global Institute. In July 2018, Kochi was ranked the topmost emerging future megacity in India by global professional services firm.