The 840s started on 1 January 840 and ended on 31 December 849.

Millennium: 1st millennium
Centuries: 8th century9th century10th century
Decades: 810s 820s 830s840s850s 860s 870s
Years: 840 841 842 843 844 845 846 847 848 849
Categories: BirthsDeathsArchitecture
EstablishmentsDisestablishments

Events change

Important people change