Spratly islands as his own, naming it the "Free Territory of Freedomland". Evidence of human presence in the region extends back nearly 50,000 years at Tabon Caves on Palawan. Therefore, it is difficult to say when humans first came upon this island group. Within historical times, several groups may have passed through or occupied the islands. Between 600 BC to 3 BC there was an east to west migration by members of the seafaring Sa Huỳnh culture. This may have led them through the Spratly Islands on their way to Vietnam. These migrants were the forebears of the Cham people, an Austronesian-speaking people that founded the Old Champa empire that ruled what was known for centuries as the Champa Sea. Early records and cartography In the Song Dynasty work Zhu fan zhi by Zhao Rugua, the name "Thousand Li Stretch of Sands" (Qianli Changsha, ) and the "Ten-Thousand Li of Stone Pools/Beds" (Wanli Shitang , or Wanli Shichuang ) were given, interpreted by some to refer to Paracel and Spratly respectively. Wanli Shitang is also recorded in the History of Yuan to have been explored by the Chinese during the Mongol-led Yuan dynasty and may have been considered by them to have been within their national boundaries. However, the Yuan also ruled over Korea, Outer Mongolia, and parts of modern Russia. They are also referenced, sometimes with different names, in the Ming dynasty. For example, in the Mao Kun map dating from Zheng He's voyage of the early 15th century, Shixing Shitang () is taken by some to mean Spratly, however different authors interpret the identities of these islands differently. Another Ming text, Haiyu (海語, On the Sea), uses Wanli Changsha () for Spratly and noted that it is located southeast of Wanli Shitang (Paracels). When the Ming Dynasty collapsed, the Qing dynasty continued to include the territory in maps compiled in 1724, 1755, 1767, 1810, and 1817, but did not officially claim jurisdiction over these islands. A Vietnamese map from 1834 also combines the Spratly and Paracel Islands into one region known as "Vạn Lý Trường Sa", a feature commonly incorporated into maps of the era () ‒ that is, the same as the aforementioned Chinese island name Wanli Changsha. According to Hanoi, Vietnamese maps record Bãi Cát Vàng (Golden Sandbanks, referring to both the Spratly and Paracel Islands), which lay near the coast of the central Vietnam, as