Decades: 790s 800s 810s 820s 830s - 840s - 850s 860s 870s 880s 890s

Years: 839 840 841 842 843 - 844 - 845 846 847 848 849

• Succession of Pope Sergius II (844 - 847).
• Rhodri the Great becomes king of Gwynedd.
• June 15: Louis II is crowned emperor.
• Dorestad is raided by Vikings.

Deaths

• January 25: Pope Gregory IV (827 - 844)
• Merfyn Frych, king of Gwynedd\n