Hong Kong is a name applied to both a single island and a political entity that includes a total of 235 islands and a still larger area on the adjacent mainland, all of which the British acquired or leased in the nineteenth century. In this chronology, Hong Kong refers to this whole region. Throughout the Pleistocene Age (approx. 1.75 million years ago to 10,000 B.C.) the islands of Hong Kong are often attached directly to the mainland of China because of the low sea level; not until the world's seas rise to their present level, about 6000 B.C., did Hong Kong's islands become isolated. Although it is quite likely that some humans visited this territory earlier, the first known traces of human beings in this region date only to about 4100 B.C. What is uncertain is whether these first inhabitants originated in Southeast Asia, South China, or Taiwan. In any case, the people of Hong Kong pass through the Neolithic (New Stone) Age and Bronze Age, in both instances for the most part adopting or at least learning from the culture of peoples in southern China and Southeast Asia. Starting about 200 B.C., mainland Chinese begin to exert increasing control over southern China; not until about A.D. 220, however, do mainland Chinese appear to be becoming an active presence in Hong Kong. By about the year 400 Hong Kong seems to be involved in trade involving both China and Southeast Asia. Several bits of physical evidence during the early first millennium strongly suggest the increasing role of mainland Chinese in Hong Kong, but it will be about 800 before Hong Kong can begin to be considered as part of China. The earliest written evidence of the Chinese settlement in the Hong Kong region appears in a ninth-century poem.
4100–3000B.C.: The oldest known evidence of human occupation in Hong Kong dates from this period, technically labeled the Middle Neolithic; it is sometimes described as that of “affluent foragers” because although these people continue to obtain most food simply by foraging, they also make quite advanced pottery and bone and shell artifacts. The first phase (Chung Hom Wan, approximately 4100–3600 B.C.) has both painted and cord-marked pottery; the second phase (Sham Wan, 3600–3000 B.C.) has