* 1723 – Mathurin Jacques Brisson, French naturalist ( d. 1806 )

* 1806 – Francis II, the last Holy Roman Emperor, abdicates ending the Holy Roman Empire.

* 1806 – Battle of Mišar during the Serbian Revolution begins.

* 1806 – Santiago de Liniers, 1st Count of Buenos Aires re-takes the city of Buenos Aires, Argentina after the first British invasion.

* 1724 – George Stubbs, English painter ( d. 1806 )

* Anton Alexander Graf von Auersperg ( 1806 – 1876 ) – Austrian poet who wrote under the pseudonym of Anastasius Grün.

The Lewis and Clark Expedition spent the winter of 1805 – 1806 at Fort Clatsop, a small log structure south and west of modern day Astoria.

* 1806 – Michael Haydn, Austrian composer ( b. 1737 )

* 1727 – Michel Adanson, French botanist ( d. 1806 )

* William Bernard Ullathorne ( 1806 – 89 )

Following his conquest of most of Western Europe, the first Napoleon made his elder brother Joseph ( 1768 – 1844 ) king first of Naples ( 1806 – 1808 ) and then of Spain ( 1808 – 1813 ), his third brother Louis ( 1778 – 1846 ) king of Holland ( 1806 – 1810 ) ( subsequently forcing his abdication after his failure to subordinate Dutch interests to those of France ) and his youngest brother Jérôme Bonaparte ( 1784 – 1860 ) king of Westphalia, the short-lived realm created from some of the states of northwestern Germany ( 1807 – 1813 ).

Dundas put a brake on intellectual and social change through his ruthless manipulation of patronage in alliance with Prime Minister William Pitt the Younger, until he lost power in 1806.

* 1719 – William Vernon, American merchant ( d. 1806 )

* Online text of The Journals of Lewis and Clark, 1804 – 1806 by William Clark and Meriwether Lewis at Project Gutenberg

* 1759 – William Pitt the Younger, English politician, Prime Minister of the United Kingdom ( d. 1806 )

* 1748 – William V of Orange, Stadtholder of the Dutch Republic ( d. 1806 )

* 1806 – William Webb Ellis, credited with the invention of Rugby ( d. 1872 )

* 1806 – Napoleonic Wars: Forces of the British Empire lay siege to the port of Boulogne in France by using Congreve rockets, invented by Sir William Congreve.

In 1804 Jefferson appointed Meriwether Lewis and William Clark as leaders of the expedition ( 1804 – 1806 ), which explored the Louisiana Territory and beyond, producing a wealth of scientific and geographical knowledge, and ultimately contributing to the European-American settlement of the West.

* William Pitt the Younger ( 1759 – 1806 ), who also served as Prime Minister ; never married.

* October 18 – William VIII, Duke of Brunswick ( b. 1806 )

* September 7 – William Barton Wade Dent, Congressman ( b. 1806 )

* May 28 – William Pitt the Younger, statesman and Prime Minister of the United Kingdom ( d. 1806 )

* March 8 – Prince William V of Orange ( d. 1806 )

These principalities were confiscated when Napoleon invaded Germany ( 1806 ) and William supported his Prussian relatives.

* January 17 – William Vernon, American merchant ( d. 1806 )

Between 1806 and 1807, British military forces tried to invade the area of the Rio de la Plata, at the command of Home Riggs Popham and William Carr Beresford, and John Whitelocke.

" King Lear and the Fool in the Storm " by William Dyce ( 1806 – 1864 )

The survey was started by William Lambton in 1806 and lasted several decades.

Commissioned into the Royal Artillery, in 1818, Lt Everest was appointed as assistant to Colonel William Lambton, who had started the Great Trigonometrical Survey of the sub-continent in 1806.

William V, Prince of Orange-Nassau ( Willem Batavus ; 8 March 1748 – 9 April 1806 ) was the last Stadtholder of the Dutch Republic, and between 1795 and 1806 he led the Government of the Dutch Republic in Exile in London.

William Pitt the Younger ( 28 May 1759 – 23 January 1806 ) was a British politician of the late 18th and early 19th centuries.

" Pitt, William ( 1759 – 1806 )", Oxford Dictionary of National Biography, ( 2004 ); online 2009 ; accessed 12 Sept 2011

For the next 17 years until 1801 ( and again from 1804 to 1806 ), Pitt, the Tory, was Prime Minister in the same sense that Walpole, the Whig, had been earlier.

Although many of the Whigs who had joined with Pitt would eventually return to the fold, joining again with Fox in the Ministry of All the Talents following Pitt's death in 1806.

The second phase of fort-building ( 1806 – 1819 ) included Fort Pitt ( later used as a hospital and the site of the first Army Medical School ).

" Pitt died in the house in 1806.

Charles James Fox PC ( 24 January 1749 – 13 September 1806 ), styled The Honourable from 1762, was a prominent British Whig statesman whose parliamentary career spanned thirty-eight years of the late 18th and early 19th centuries and who was particularly noted for being the arch-rival of William Pitt the Younger.

When Pitt died on 23 January 1806, Fox was the last remaining great political figure of the era, and could no longer be denied a place in government.

Fox died – still in office – at Chiswick House, west of London, in 1806, not eight months after the younger Pitt.

In the long-term the Grenvillites were revived by William Pitt the younger who served as Prime Minister from 1784 and dominated British politics until his death in 1806.

William Pitt the Younger, who made it his home for twenty years — longer than any First Lord before or since — from 1783 to 1801 and from 1804 to 1806, referred to it as " My vast, awkward house.

Pitt died in January 1806.

When William Pitt died in 1806, the King asked Liverpool to accept the post of Prime Minister, but he refused, as he believed he lacked a governing majority.

* John Pitt, 2nd Earl of Chatham 1801 – 1806

** United Kingdom of Great Britain and Ireland: King George III ( 1801 – 1820 ); Prince Regent George ( 1811 – 1820 ); Prime Ministers William Pitt the Younger ( 1801, 1804 – 06 ), Henry Addington ( 1801 – 04 ), The Lord Grenville ( 1806 – 07 ), The Duke of Portland ( 1807 – 09 ), Spencer Perceval ( 1809 – 1812 ), The Earl of Liverpool ( 1812 – 1827 )

Having in 1804 been chosen to represent Liskeard, he was on the restoration of the Pitt ministry appointed secretary of the treasury, holding office till the dissolution of the ministry after the death of Pitt in January 1806.

Arguably the first national unity government in any country was the " Ministry of All the Talents " that led the United Kingdom for about a year after the death of William Pitt the Younger in 1806, during the Napoleonic Wars.

* William Pitt the Younger ( 1759 – 1806 ), his son and Prime Minister of Great Britain 1783 – 1801 and 1804 – 1806