The urban civilisation and advanced agriculture of north China acted as a lure to the neighbouring peoples from beyond the frontiers of the Middle Kingdom. When early Han China suffered recurrent attacks from the Xiongnu tribes to the north-west its armies retaliated by going on the offensive. They fought battles and established military colonies across Central Asia as far west as Kashgar and the borders of Ferghana.

The hilly island of Hong Kong (no 1 on the map above) was first offered to Great Britain in 1841 during the First Anglo-Chinese War, or 'Opium War'. The following year, under the Treaty of Nanjing, it was ceded 'to be governed by such laws as Her Majesty the Queen of Great Britain etc. may see fit to direct'.

Portuguese merchant venturers began to explore the south China coast in the early 16th century. After discovering Japan in 1542 they traded Chinese silk there and were anxious to obtain a base of their own on the China coast, but Chinese law made this impossible and instead a number of Portuguese sailors found themselves imprisoned. In 1556, however, they gained permission for limited trading access to Guangzhou, and negotiated the lease of a small peninsula which they were already occupying on the coast nearby, known as Oumen, 'Gateway to the Bay'.