Hong Kong: Last week German Chancellor Angela Merkel hosted visiting Chinese President Xi Jinping at a dinner where they exchanged gifts. Merkel presented to Xi a 1735 map of China made by prolific French cartographer Jean-Baptiste Bourguignon d'Anville and printed by a German publishing house.

According to an antique-maps website, d'Anville's map was based on earlier geographical surveys done by Jesuit missionaries in China and represented the "summation of European knowledge on China in the 18th-century."

A detail of the 1735 d'Anville map showing ''China Proper''.

The map showed, according to its original Latin caption, the so-called "China Proper" -- that is, the Chinese heartland mostly populated by ethnic Han people, without Tibet, Xinjiang, Mongolia, or Manchuria. The islands of Taiwan and Hainan -- the latter clearly part of modern China, the former very much disputed -- are shown with a different colour border.

Historical maps are sensitive business in China. Every schoolchild in China learns that Tibet, Xinjiang, Taiwan, and the Diaoyu Islands (known as Senkaku in Japanese) have been "inalienable parts of China since ancient times."