The Ancient Ryukyus generally refers to the period from the 12th century, at the beginning of the Gusuku (Castle) Period, through to the establishment of the Ryukyu Kingdom, to the invasion of the Ryukyus by the Shimazu Clan from Kyushu in 1609.
In 12th century Okinawa, the long Shell Mound period, where people lived a hunter-gatherer lifestyle, was coming to an end as an agrarian society was formed. In conjunction with this, regional chieftains, called Aji, gathered political power in their respective areas, built castles, called Gusuku, for fortresses and struggles for overall political power began. This is called the Gusuku Period.
By the 14th century three great houses had developed and Okinawa was divided into three centers of power; the south, called Nanzan, the central area, called Chuzan, and the north, called Hokuzan. This was called the Sanzan or Three Kingdoms Period. The kingdoms had good ports and started to conduct active trading with China to increase their economic power.
In the 15th century one of the leaders from the south, Sho Hashi, succeeded in unifying the three kingdoms. The Ryukyu Kingdom was born.

Establishment of a Unified Royal Court

The Ryukyu Kingdom built up trading relationships with China, East Asia, Korea, Japan, and other neighboring Asian and East Asian nations. This era has been called The Great Age of Trade.

The Ryukyu Islands in the Age of Great Trade

The First Ryukyu Dynasty founded by Sho Hashi was succeeded by the Second Ryukyu Dynasty. Among the greatest of the kings was King Sho Shin, the third to ascend the throne in the second dynasty. During his reign, the kingdom was thoroughly organized, power was centralized and many construction projects were carried out. Sho Shin's reign is suitably called the Golden Age of the Ryukyus.

Establishment of the Ryukyu Kingdom

During the Ancient Ryukyu period, Okinawa received influences from Japan and Asia. It experienced a blossoming of its own distinctive history and culture while forming and developing itself as an independent nation. But in 1609, due to a military invasion by the Shimazu Clan, the kingdom functionally lost its independence as a sovereign nation and became closely tied to the Shogunate system in Japan.