Year 726 (DCCXXVI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. The denomination 726 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
|Ab urbe condita||1479|
|Balinese saka calendar||647–648|
|Chinese calendar||乙丑年 (Wood Ox)|
3422 or 3362
— to —
丙寅年 (Fire Tiger)
3423 or 3363
|- Vikram Samvat||782–783|
|- Shaka Samvat||647–648|
|- Kali Yuga||3826–3827|
|Japanese calendar||Jinki 3|
|Minguo calendar||1186 before ROC|
|Seleucid era||1037/1038 AG|
|Thai solar calendar||1268–1269|
852 or 471 or −301
— to —
853 or 472 or −300
- Emperor Leo III issues a series of edicts banning the veneration of images (726–729), and launching the iconoclastic controversies. Most of the clergy – particularly in Italy and Greece – are opposed to these edicts with uncompromising hostility, and in the western parts of the Byzantine Empire the people refuse to obey his religious reforms.
- Arab–Byzantine War: Muslim forces under Maslama ibn Abd al-Malik resume their expedition against Anatolia (modern Turkey). In a large-scale raid they plunder the fortress city of Caesarea.
- Umayyad conquest of Gaul: Muslim raiders under Abdul Rahman al-Ghafiqi, current governor of Septimania, devastate Avignon, Viviers, Valence, Vienne and Lyon (approximate date).
- Marcello Tegalliano dies after a 9-year reign. Uprising in Venice against Byzantium. The cause of mass unrest was the iconoclastic decrees of Emperor Leo III. A few days later, political demands were put forward for wide autonomy within the Byzantine Empire and the right to appoint the ruler of the region - Doge. The rebels elect Orso Ipato the Doge of Venice. Desiring to preserve the proceeds of the treasury from the second most important port of the Byzantine Empire and not having the resources to cope with a well-fortified and armed region, Byzantium agrees with all the requirements put forward. Orso Ipato recognised by Leo III, who gives him the title hypatos. The Venetian fleet, led by Orso Ipato, frees Ravenna from the Lombards and restores the power of the Byzantine governor there.
- Seismic activity in the Mediterranean Sea: The volcanic island of Thera erupts, while the city of Jerash (in present-day Jordan) suffers a major earthquake.
- King Ine of Wessex resigns his crown, and travels on a pilgrimage to Rome. He is succeeded by his brother-in-law (and probably distant cousin) Æthelheard.
- Dúngal mac Selbaig is deposed as king of Dál Riata (Scotland). He is succeeded by Eochaid mac Echdach (a son of former king Eochaid mac Domangairt).
- October 22 – Itzamnaaj K'awiil, the ruler of the Mayan city state at Dos Pilas in Guatemala since 698, dies after a 28-year reign.
- Treadgold. History of the Byzantine State, pp. 350, 352–353
- Treadgold (1997), p. 349
- Yorke. Kings and Kingdoms, p. 147
- Lifshitz, Felice (2014). Religious Women in Early Carolingian Francia: A Study of Manuscript Transmission and Monastic Culture. Fordham University Press. p. 303. ISBN 9780823256891.