|830 by topic|
|Ab urbe condita||1583|
|Balinese saka calendar||751–752|
|Chinese calendar||己酉年 (Earth Rooster)|
3526 or 3466
— to —
庚戌年 (Metal Dog)
3527 or 3467
|- Vikram Samvat||886–887|
|- Shaka Samvat||751–752|
|- Kali Yuga||3930–3931|
|Japanese calendar||Tenchō 7|
|Minguo calendar||1082 before ROC|
|Seleucid era||1141/1142 AG|
|Thai solar calendar||1372–1373|
956 or 575 or −197
— to —
957 or 576 or −196
Year 830 (DCCCXXX) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar.
- King Wiglaf of Mercia regains control from Wessex, and returns to the throne.
- June 5 – Emperor Theophilos, 16, marries the Armenian noblewoman Theodora, in the Hagia Sophia at Constantinople. He chooses her during a representation of a bride-show; she becomes empress (Augusta) of the Byzantine Empire.
- Byzantine–Arab War: Muslim reinforcements from Ifriqiya and Al-Andalus (modern Spain) defeat Byzantine forces under Theodotus in Sicily, but a plague once again compels them to retreat to Mazara del Vallo, and evacuate to North Africa.
- Emperor Louis the Pious returns from a campaign in Brittany, and is captured by his son Pepin I, king of Aquitaine. He is put under house arrest at Compiegne, and his wife Judith is incarcerated at Poitiers.
- The Ad-dimnah Hospital (bimaristan) is created in Kairouan (modern Tunisia), by the Aghlabid emir Ziyadat Allah I.
- Nennius, Welsh abbot of Bangor Fawr, compiles the Historia Brittonum. He is also known for the Historia's list of the 12 battles of King Arthur (approximate date).
- Hirsau Abbey (modern Germany) is founded by the Rhenish Franconian count Erlafried of Calw (approximate date).
- Ansgar, a Frankish missionary, visits the trade city Birka, located at Lake Mälaren in Sweden (approximate date).
- Adalard, Frankish nobleman (approximate date)
- Athanasius I, bishop of Naples (d. 872)
- Carloman of Bavaria, Frankish king (or 828)
- Charles, Frankish bishop (or 825)
- Engelberga, Frankish empress (approximate date)
- Irmgard, Frankish abbess (or 833)
- Ishaq ibn Hunayn, Muslim physician (approximate date)
- Junayd of Baghdad, Muslim Sufi (d. 910)
- Kōkō, emperor of Japan (d. 887)
- Lambert III, Frankish nobleman (d. 882)
- Naum of Preslav, Bulgarian writer (approximate date)
- Robert the Strong, Frankish nobleman (approximate date)
- Rimbert, Frankish archbishop (d. 888)
- Rurik, prince of Novgorod (approximate date)
- Wulgrin I, Frankish count (approximate date)
- Yahya ibn Mu'adh al-Razi, Muslim Sufi (d. 871)
- Yunju Daoying, Chinese Buddhist teacher (d. 902)
- Æthelwold, bishop of Lichfield
- Ashot I, prince of Iberia (or 826)
- Eardwulf, king of Northumbria (approximate date)
- Egfrid, bishop of Lindisfarne
- Li Jiang, chancellor of the Tang Dynasty (b. 764)
- Sa'id ibn Aws al-Ansari, Muslim linguist
- Wang Jian, Chinese poet (approximate date)
- Zhang Ji, Chinese scholar and poet (approximate date)
- ^ Swanton, Anglo-Saxon Chronicle, pp. 62–63.
- ^ "Al-Qayrawan hospital, Tunisia in 830". Archived from the original on April 25, 2012. Retrieved November 8, 2011.