 Though it is not known just when the area first became organized as a functioning port city, it was active as such by the time of the unification of the Ryūkyū Kingdom in the early 15th century.Though today Naha has grown to incorporate the former royal capital city of Shuri, center of Chinese learning Kumemura, and other towns and villages, in the period of the Ryūkyū Kingdom, it was a smaller city, prominent as a major port, but not as a political center.Medieval Naha was on a tiny island called Ukishima, connected to the mainland of Okinawa Island by a narrow causeway called which led on to Shuri.