Year 873 (DCCCLXXIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar.
Carloman, son of King Charles the Bald, is hailed before a secular court and condemned to death – for plotting against his father. He is blinded, but avoids imprisonment by escaping to the East Frankish Kingdom, where his uncle, Louis the German, gives him protection.
Al-Andalus: The city of Toledo (modern Spain) rises up for a second time against Umayyad rule, due to ethnic tensions in two years.
The Danish Great Heathen Army, led by the Viking leaders Halfdan and Guthrum, attack Mercia and capture the royal centre at Repton (Derbyshire). The Vikings establish an encampment with a U-shape ditch, on the south bank of the River Trent and spend the winter there.
Muhammad ibn Tahir, Muslim governor of Khorasan, is overthrown by the Saffarids, led by Ya'qub ibn al-Layth, who conquer the capital, Nishapur. Khorasan is annexed to their own empire in eastern Persia. The Tahirid Dynasty falls.
August 15 – Emperor Yi Zong (Li Cuī) dies after a 13-year reign. He is succeeded by his 11-year-old son Xi Zong, as ruler of the Tang Dynasty. During his reign, a widespread failure of the agricultural harvest leads to famine (which causes people to resort to cannibalism) and agrarian rebellions.
Abdullah al-Mahdi Billah, Muslim caliph (d. 934)
Abu Yazid, Kharijite Berber leader (d. 947)
Ahmad al-Muhajir, Muslim imam (d. 956)
Al-Tabarani, Muslim hadith scholar (d. 970)
Fujiwara no Sadakata, Japanese poet (d. 932)
Ordoño II, king of Galicia and León (d. 924)
Al-Kindi, Muslim philosopher and polymath
Du Cong, chancellor of the Tang Dynasty (b. 794)
Ecgberht I, king of Northumbria
July 8 – Gunther, archbishop of Cologne
Hunayn ibn Ishaq, Muslim scholar and physician (b. 809)
Ivar the Boneless, Viking leader (approximate date)
John III, Syriac Orthodox patriarch of Antioch
Kang Chengxun, general of the Tang Dynasty
Lethlobar mac Loingsig, king of Ulaid (Ireland)
Malik ibn Tawk, Muslim governor
Muhammad ibn Ali al-Armani, Muslim general
Rodrigo, Asturian nobleman
Rodulf Haraldsson, Viking leader
Shinshō, Japanese Buddhist monk (b. 797)
August 1 – Thachulf, duke of Thuringia
Vímara Peres, Asturian nobleman
Wei Baoheng, chancellor of the Tang Dynasty
August 15 – Yi Zong, emperor of the Tang Dynasty (b. 833)
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