Compiled between 627-659 CE -The earliest mention of the islands of present day Ryukyu, according to Ah Xiang, was in the Bei Shi or History of the Northern Dynasties (386-618),[1] as "an island country in the East China Sea, which could be reached by sailing for five days. Bei Shi stated that Ryukyu was full of caves; that it had three circles of defense-purpose fences, with water flowing by the fences; that its king was named Huan-si-shi, with a first name of Ke-ci-dou and 16 palace rooms decorated with inscriptions of animals; that their people were in constant fights with each other; that various villages were ruled by a chief called Niao-lian-shuai; that it had 4-5 marshals in charge of various caves; and that they were cannibals eating dead bodies of enemies and family members."[2]  

Compiled between 636-656 CE, the Sui Shu, or History of the Sui Dynasty (581-618), is the first specific mention of the “Country of Liuqiu”. While Chinese influences had already spread into the Korean Peninsula and as far as Japan, many parts of Asia were uncharted frontier territories. Legend has it that in 607 Emperor Yangdi dispatched his envoy Zhu Kuan to explore beyond the horizon and to find, amongst other things, the secrets of immortality and transforming base metals into gold. Discovering islands that conjured up images of floating globes he named them 'Liuqiu.' Vagueness in the Sui Shu, the annals covering the Sui era, ensures that the precise location of Zhu Kuan’s Liuqiu will forever be unclear, yet over time it came to specifically pertain to Okinawa Island and the archipelago of which it is a part, particularly as informal trade and cultural relations with China developed over the following Tang and Song Dynasties. Japan’s recognition of the Chinese naming of the islands came in a letter to King Sho Shisho of Chuzan from the Ashikaga Shogun Yoshimochi in 1416, addressing him as 'Lord of Ryukyu,' or Riukiu koku no yo no nushi. http://www.niraikanai.wwma.net/pages/wildhorse/chap1-2.html

Completed in 797 CE - Shoku Nihongi, a Heian period official history of Japan (794-1185). As Josef Kreiner summarizes, the Shoku Nihongi mentions the tributes sent from the islands of Tane, Yaku, Amami, and Tokuno, amongst others, to the imperial court in 699 A.D. The important aspect of this record is that these tributes were forwarded to the Ise Shrine, implying that they were regarded as Japanese, not foreign. The ship of the Japanese ambassador Kibi no Makibi laid anchor at the island of Okinawa during his second visit to the Tang Court of China in 753 A.D. This is the first instance in which the name Ajinawa = Okinawa is mentioned in historical records. It is explained as oki meaning "high sea" and nawa meaning "rope," but would be more plausible if we interpret aji as "local lord" and nawa as "fishing territory."[3]

The Main Okinawan History Texts

The first official narrative history of Ryukyu was the Chuuzan seikan, or Mirror of the Ages of the Chuzan Kingdom. It was completed in 1650 by the Chancellor, or sessei Shou Jou Ken, and was deliberately written in kanbun, a Japanese form of classical Chinese writing.[4] Far removed from the ancient periods of history and without much in the way of evidence to back anything up, Shou Jou Ken mixed stories passed down from generation to generation with a healthy dose of legend creation. This was particularly the case in the story of Tametomo, an exiled warrior from Japan whose son became King Shunten, ruling from 1187-1237.  Partly out of fear of retribution from the new rulers of Ryukyu, the Satsuma fiefdom, and partly because he was a realist in the new era and saw Japanese influence henceforth outweighing Chinese influences, he sought to align the people of Ryukyu more closely with Japan from ancient times onwards. In one of his most famous statements he argued that:  

"There is no doubt that in the early days after the creation of man, people came from Japan to inhabit this land (Okinawa). Accordingly, even now terms denoting heaven and earth, the mountain and river, the human body, moral principles, and birds and beasts as well as plants and trees are common to the both places. Some difference in language is attributable to the fact that this land is lying far from Japan proper and that communications between the two places were interrupted for a long time."[5]

First compiled between 1697-8, the Rekidai Hoan, Precious Documents from all Historical Eras, is a large collection of Chinese documents detailing Ryukyuan overseas voyages to China, Korea, and eight Southeast Asian countries from 1424-1867. It was kept by successive kings covering almost 450 years of both investiture and trade missions.

Compiled in two parts between 1697-1701 (7 Sai Taku volumes), and 1724-1874 (14 Sai On volumes), the Chuzan Seifu, or Genealogy of the Chuzan Kingdom was a history written in Chinese.

Compiled from 1745-1876, another official history of Ryukyu was the Kyuuyou, or Chronicle of Ryukyu.

Perhaps the most interesting of all of the principle written historical resources is the Omoro Saushi, or Anthology of the Poems of Sentiments. Although the first volume was not compiled until 1531-32 (Volume II in 1613, and Volume III in 1623) the Omoro contains poems and songs describing life in Okinawa and Amami from as far back as the early 12^th century. Prior to the 17^th century, history was transferred orally from generation to generation in songs and poems and always in the various dialects of Ryukyuan. These provide clues to the nature of society and culture from the 12^th to the 17^th century. As such, they constitute the earliest tangible record of Okinawa's history. They were gathered together and committed to paper in the 17^th century, but in such a way that scholars still struggle to find objective meaning in some of the texts. Scribes, often barely familiar with Ryukyuan, attempted to render original verses into Japanese. While dedicated scholars have spent decades trying to decipher meaning and have been able to offer interpretations for most of the verses there are still sections which remain largely indecipherable.

In the Miyako region the Omoro equivalent is the Aagu or Ayagu.