840s deaths

Darma U Dum Tsen (), better known as Langdarma (, "Mature Bull" or "Darma the Bull"), was the last king of the Tibetan Empire who in 838 killed his brother, Tritsuk Detsen, then reigned from 841 until his assassination in 842. His reign led to the dissolution of the Tibetan Empire, which had extended beyond the Tibetan Plateau to include the Silk Roads with the Tibetan manuscript center at Sachu (Dunhuang), and neighbouring regions in China, Afghanistan, and India. He was assassinated by a Buddhist monk Lhalung Pelgyi Dorje.

The third and greatest Amir of Tahirid Emirate (828–845)

Dutch bishop and saint

Duke of Croatia

The son of Asad bin Saman and Amir of Samarkand (819–841)

Irish writer

9th-century Abbasid military general and governor

Byzantine monk

Byzantine writer

Viking leader

Moduin, Modoin, or Mautwin (, , c.770–840/3) was a Frankish churchman and Latin poet of the Carolingian Renaissance. He was a close friend of Theodulf of Orléans, a contemporary and courtier of the emperors Charlemagne and Louis the Pious, and a member of the Palatine Academy. In signing his own poems he used the pen name Naso in reference to the cognomen of Ovid. From 815 (or earlier) until his death he was the Bishop of Autun.

Chinese Tang Dynasty official

abbasid Governor of Yemen (835-839)

Chinese Chancellor