As the world reels from US President Donald Trump's tariffs onslaught, here is a look back at some major trade wars since the 19th century:

In the mid-19th century, two conflicts over the opium trade, which became known as the Opium Wars, pitted China against the British Empire.

The first began in 1839, when Britain launched a military expedition to force China to open its market to Indian opium sold by British merchants.

Britain won the clash in 1842, with success going beyond opium as China was forced to give up the region of Hong Kong, open five ports to world trade, and limit its customs tariffs to five percent.

In the second Opium War, from 1856-1860, Britain allied with France, and again the imperial power came out on top, forcing China to open up eleven additional ports to foreign trade and maintain diplomatic relations with the West.

In 1890, William McKinley -- then a Republican lawmaker, later a US president -- saw through a new law that slapped an average tariff of nearly 50 percent on imports into........

© International Business Times