In four islands, including Spratly, Namyit, Sin Cowe, and Sand Cay, and six other islands, archaeologists have found vestiges and artifacts from the Early Iron Age, which is approximately the same as the time of Late Sa Huynh - Early Champa culture in Central Coast Vietnam. They include a range of vestiges, ceramic and glazed terra-cotta artifacts dated from the time of Tran Dynasty (the 14th Century), Le-Nguyen Dynasties and the early 20th Century as well. Analyzing and comparing archaeological materials from the prehistoric and early-historic time found in the Central Coastal areas and offshore islands, the author affirms that about 2,000 to 2,500 years ago, ancient Viet people already conquered, inhabited, possessed and exploited archipelagos inside Vietnam's territorial waters in East Sea.