Isla Arabio could be also interpreted as Amboyna Cay, because the position is extreme undefined. The map showes also the Paracel island group , named as Paracel dos Tavaquerro.

The detailed Spain map 'Tabula orbis cogniti universalior', drawn by an unknown geographer from 1531 shows only Borneo and between Borneo and Vietnam several black points without any name. This map also showed not the Paracel Group. During this time the Spratly Group was known by the Portugese, as a letter to the Portugese Vizeking of India sayed. Alfrede de Amalanche, a geographer of a Portugese exppedition to Chinas coast line, sayed "there are several small sandy islands, we fronted on the way back from the Maccao Place to West India. All islands are located on a wide drying ground, where navigation is dangerous all the time. Some of these islands are inhabited by Chinese monks and several buildings stands on the larger islets". In 1537 the Portugese de Pinto sailed along the vietnams shores and named the Paracel Islands as Ilhas dos Tavaquerro.

In 1595 several Netherlande merchant ships reported also of a large number of sandy islets mid into the sea. between Borneo and the shores of Vietnam. 1599 till 1601 the HNetherlande van Noort explored the shores of north western Borneo and drifted up towards north and found several islands, surrounded by large coral reefs. In 1602 the Netherlande Admiral Wybrand van Warwijck sailed through the most unnamed islands, and reported of a name as Nuang Hyn for the islands fronting the northwestern Borneos shores. In 1618 the Netherlande Vizeking Pieterzoon Coen annexed most of the islands fronting the north western Borneo shores.

Source: http://community.middlebury.edu/~scs/docs/Schippke/sprat_h.html

Below are two documents in the early 1900s that deal with placing the Paracel (Hoang Sa) Islands and the Spratly (Truong Sa) Islands under the administrative governance of Vietnam's Thua Thien and Ba Ria provinces, respectively.