1800s

The 1800s was the decade that began on January 1, 1800 and ended on December 31, 1809. It is distinct from the decade known as the '''181st decade''' which began on January 1, 1801 and ended on December 31, 1810.

 Events 
Beginning of the Napoleonic Wars (1803–1815). 
Semaphore is adopted by navies. 
The United Kingdom was founded (1801)

 World leaders 
 Emperor Napoleon I (First French Empire)
 Emperor Francis II (Holy Roman Empire)
 Frederick William III of Prussia (Prussia)
 Pope Pius VII
 Tsar Paul I (Russia)
 Tsar Alexander I (Russia)
 King Charles IV (Spain)
 King George III, (United Kingdom)
 President John Adams (United States)
 President Thomas Jefferson (United States)
 Fath Ali Shah of Qajar dynasty (Persia)
 Jiaqing Emperor of China (Qing Dynasty)

 Births 

 Deaths