Dejima, a small artificial island, was created in 1634 by Shogun Iemitsu solely to house foreign traders, sailors and physicians. It also prevented the Portuguese from spreading Christianity, which had become a concern after the Shimabara rebellion in 1637. Travel between the island and the mainland was strictly forbidden, except with special permission. Occasionally scholars would travel to Dejima, or western physicians would travel to the mainland in order to treat an influential Japanese person. The island was originally home to the Portuguese, but after 1637 the Dutch were given control of the island while the rest of the foreigners were expelled. Interestingly, owing to the formation in the Netherlands of the Batavian Republic with the help of Napoleonic France, Dejima was the only place in the world where the royal Dutch flag was flown between 1795 and 1806.
