Centuries: 18th century - 19th century - 20th century

Decades: 1750s 1760s 1770s 1780s 1790s - 1800s - 1810s 1820s 1830s 1840s 1850s

Years: 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809

• Beginning of the Napoleonic Wars (1803 - 1815).
• Semaphore is adopted by navies.