1840s

Technology

 * First use of in an operation, by
 * The first sent by  on,  from  to.

War, peace and politics

 * First signing of the (Te Tiriti o Waitangi) on, 1840  at   . The treaty between the  and  made New Zealand a British  and is considered the founding point of modern New Zealand.
 * The, signed , , settled the dispute over the location of the border between the  and.
 * On, , the first of two ended between  and  with the .  One of the consequences was the  of parts of modern day  to the British.  Hong Kong would eventually be returned to China in.
 * ( - ) was fought between and the . The latter emerged victorious and gained undisputed control over  while annexing portions of,  and.
 * Wave of s in . Collectively known as the . This led to mass emigration of these refugees into industrial cities of the United States as well as to other locations around the world.
 * and writes , first published on,.

Culture and religion

 * - Persian Prophet the announces his revelation, founding . He announced to the world of the coming of "." He is considered the forerunner of, the founder of the.
 * becomes a leader.
 * In the midst of the, preacher predicts the  of  will occur on , . Christ's failure to appear became known as the.
 * invents the, receiving the patent on ,.
 * writes The Principles of Political Economy, first published in 1848
 * publishes ', ', ' and '

Economics
In the mid 1840s several harvests failed across Europe, which caused famines. Especially the (-) was severe and caused a quarter of 's population to die or emigrate to the United States and Canada.

Other

 * Introduction of the . The first of them is, issued by the on ,.

World leaders

 * Emperor
 * Chancellor
 * Emperor
 * King
 * King
 * Emperor
 * Queen
 * King
 * King
 * Queen
 * Prime Minister
 * Prime Minister Sir
 * Prime Minister
 * President
 * President
 * President
 * President
 * President
 * President
 * President
 * Sultan
 * s of
 * , (b. - d. )  Shah from -1848
 * , 1848-
 * s of
 * , (b. - d. )  Shah from -1848
 * , 1848-