Editing 1840s (section)

=== Northern Europe ===

==== Sweden ====
* [[1842]] – Compulsory [[education in Sweden|elementary education]] introduced.
* [[March 8]], [[1844]] – [[Monarch|King]] [[Oscar I of Sweden|Oscar I]] ascends to the throne of [[Sweden-Norway]] upon the death of his father [[Charles XIV John of Sweden|Charles XVI/III John]].

==== Denmark ====
{{Main|History of Denmark|History of Iceland|Danish colonial empire}}
* [[1843]] – The [[Denmark|Danish]] government re-establishes the [[Althing]] in [[Iceland]] as an advisory body.
* [[March 24]], [[1848]] – Start of the [[First Schleswig War]] ({{langx|de|Schleswig-Holsteinischer Krieg}} or Three Years' War ({{langx|da|Treårskrigen}})). The [[First Schleswig War]] was the first round of military conflict in southern [[Denmark]] and northern Germany rooted in the [[Schleswig-Holstein Question]], contesting the issue of who should control the Duchies of [[Schleswig]] and [[Holstein]]. The war, which lasted from 1848 to 1851, also involved troops from [[Kingdom of Prussia|Prussia]] and [[Sweden]]. Ultimately, the war resulted in a Danish victory. A second conflict, the [[Second Schleswig War]], erupted in 1864.
* [[June 5]], [[1849]] – [[Denmark]] becomes a [[constitutional monarchy]].

==== United Kingdom ====
* [[September 16]], [[1840]] – [[Joseph Strutt (philanthropist)|Joseph Strutt]] hands over the deeds and papers concerning the [[Derby Arboretum]], which is to become [[England]]'s first public park.
* [[August 10]], [[1842]] – The [[Mines and Collieries Act 1842|Mines Act 1842]] becomes law, prohibiting underground work for all women and boys under 10 years old in [[England]].
* [[March 25]], [[1843]] – [[Marc Isambard Brunel]]'s [[Thames Tunnel]], the first tunnel under the [[River Thames]] and the world's first bored underwater tunnel, is opened in London.<ref name="Pocket On This Day"/>
* [[May 4]], [[1843]] – [[Colony of Natal|Natal]] is proclaimed a British colony.
* April – The [[Fleet Prison]] for [[debtors' prison|debtors]] in London is closed.
[[File:Chartist meeting, Kennington Common.jpg|thumb|[[April 10]]: "Monster Rally" of [[Chartism|Chartists]] held on [[Kennington Common]] in London; the first photograph of a crowd depicts it.]]
* [[July]], [[1848]] – [[Public Health Act 1848|Public Health Act]] establishes [[Local board of health|Boards of Health]] across [[England and Wales]], the nation's first public health law, giving cities broad authority to build modern sanitary systems.<ref name=CBH_269>{{cite book|last1=Palmer|first1=Alan|last2=Palmer|first2=Veronica|year=1992|title=The Chronology of British History|publisher=Century Ltd|location=London|pages=269–270|isbn=978-0-7126-5616-0}}</ref>

===== Royalty =====
[[Queen Victoria]] was on the throne 20 June 1837 until her death 22 January, 1901. The [[wedding of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha]] took place in 1840.

===== Ireland =====
The [[Great Famine (Ireland)|Great Famine]] of the 1840s caused the deaths of one million Irish people and over a million more emigrated to escape it.<ref>{{cite web|title=The Irish Potato Famine |publisher=Digital History |date=7 November 2008 |url=http://www.digitalhistory.uh.edu/historyonline/irish_potato_famine.cfm |access-date=2008-11-08 |url-status=dead |archive-url=https://web.archive.org/web/20120823030816/http://www.digitalhistory.uh.edu/historyonline/irish_potato_famine.cfm |archive-date=23 August 2012 }}</ref> It is sometimes referred to, mostly outside Ireland, as the "Irish Potato Famine" because one-third of the population was then solely reliant on this cheap crop for a number of historical reasons.<ref>{{citation|title=The Great Hunger|first=Cecil|last=Woodham-Smith|year=1991|page = 19}}</ref><ref>{{citation|title=This Great Calamity|last=Kinealy|first=Christine |year=1994|publisher=Gill & Macmillan|isbn=978-0-7171-4011-4|pages = xvi–ii, 2–3}}</ref><ref>{{citation|title=The Irish Potato Famine|last=O'Neill|first=Joseph R.|year=2009|publisher=ABDO| isbn=978-1-60453-514-3|url=https://books.google.com/books?id=TVEWfeClF8MC|page = 1}}</ref> The [[Proximate cause#Historiographical usage|proximate cause]] of [[famine]] was a potato disease commonly known as [[potato blight]].<ref>{{citation|title=Ireland's Great Famine: Interdisciplinary Perspectives|first=Cormac|last=Ó Gráda|year=2006|publisher=Dublin Press|isbn=978-1-904558-57-6|page = 7}}</ref> A census taken in 1841 revealed a population of slightly over 8 million.<ref>{{citation|publisher=Gill and Macmillan Ltd|first=Richard|last=Killen|year=2003|title=A Short History of Modern Ireland}}</ref> A census immediately after the famine in 1851 counted 6,552,385, a drop of almost 1.5 million in 10 years.<ref>{{citation|last1=Vaughan|first1=W.E|last2=Fitzpatrick|first2= A.J|editor1=W. E. Vaughan|editor2=A. J. Fitzpatrick|title=Irish Historical Statistics, Population, 1821/1971|publisher=[[Royal Irish Academy]]|year=1978}}</ref>

The period of the potato blight in Ireland from 1845 to 1851 was full of political confrontation.<ref>{{citation|last=Donnelly| first=James S. Jr. |title=Mass Eviction and the Irish Famine: The Clearances Revisited", from The Great Irish Famine|editor-first=Cathal|editor-last=Poirteir|publisher=Mercier Press|location=Dublin, Ireland|year=1995}}</ref> A more radical [[Young Ireland]] group seceded from the Repeal movement and attempted an armed rebellion in the [[Young Irelander Rebellion of 1848]], which was unsuccessful.