917

917 in various calendars
Gregorian calendar	917; CMXVII
Ab urbe condita	1670
Armenian calendar	366; ԹՎ ՅԿԶ
Assyrian calendar	5667
Balinese saka calendar	838–839
Bengali calendar	324
Berber calendar	1867
Buddhist calendar	1461
Burmese calendar	279
Byzantine calendar	6425–6426
Chinese calendar	丙子年 (Fire Rat); 3614 or 3407; — to —; 丁丑年 (Fire Ox); 3615 or 3408
Coptic calendar	633–634
Discordian calendar	2083
Ethiopian calendar	909–910
Hebrew calendar	4677–4678
Hindu calendars
- Vikram Samvat	973–974
- Shaka Samvat	838–839
- Kali Yuga	4017–4018
Holocene calendar	10917
Iranian calendar	295–296
Islamic calendar	304–305
Japanese calendar	Engi 17; (延喜１７年)
Javanese calendar	816–817
Julian calendar	917; CMXVII
Korean calendar	3250
Minguo calendar	995 before ROC; 民前995年
Nanakshahi calendar	−551
Seleucid era	1228/1229 AG
Thai solar calendar	1459–1460
Tibetan calendar	阳火鼠年; (male Fire-Rat); 1043 or 662 or −110; — to —; 阴火牛年; (female Fire-Ox); 1044 or 663 or −109

Millennium:	1st millennium
Centuries:	9th century; 10th century ; 11th century;
Decades:	890s; 900s; 910s ; 920s; 930s;
Years:	914; 915; 916; 917 ; 918; 919; 920;

Year 917 (CMXVII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.

Events

August 20 – Battle of Achelous: A Byzantine expeditionary force (62,000 men) under General Leo Phokas (the Elder) is routed by the Bulgarians at the Achelous River near the fortress of Anchialos (modern Pomorie) on the Black Sea coast. Phokas flees to Mesembria (modern Nesebar) and escapes by boarding a ship. Tsar Simeon I (the Great) becomes de facto ruler of the whole Balkan Peninsula, except the well-protected Byzantine capital of Constantinople and the Peloponnese.^[1]
Fall – Battle of Katasyrtai: The Bulgarian army under Simeon I marches southwards to Constantinople. Leo Phokas, who survived at Anchelous, gathers the last Byzantine troops to intercept the Bulgarians before they reach the capital. The two armies meet near the village of Katasyrtai, just outside Constantinople. After a surprise night attack, the Byzantines are completely routed from the battlefield.^[2]

Bulgarian–Serbian War: Simeon I sends a Bulgarian expeditionary force under Theodore Sigritsa and Marmais to Serbia. The two persuade Petar Gojniković, a Serbian prince who formed an anti-Bulgarian coalition, to meet for a peace agreement. They seize him and send the rebellious prince to the Bulgarian capital of Preslav, where he dies in prison. Simeon replaces Petar with Pavle Branović, a grandson of prince Mutimir, who lives in Preslav. Serbia becomes a puppet state until 921.^[3]
The Hungarians, after attacking Swabia, sack and burn Basel (modern Switzerland). They invade Lorraine in Lotharingia, destroying Verdun and Moyenmoutier, and many monasteries in Alsace. Duke Arnulf I (the Bad) with Hungarian military aid, reconquers his land from King Conrad I of the East Frankish Kingdom. After this event, Bavaria and Swabia agree to pay tribute to the Hungarians.
Battle of Confey: The Norse Vikings under Sigtrygg Caech defeat and kill King Augaire mac Ailella of Leinster in battle. Sigtrygg re-captures Dublin and establishes himself as king, while his kinsman Ragnall ua Ímair returns to England to become King of Northumbria.

Summer – Lady Æthelflæd of Mercia cements an alliance with King Constantine II of Scotland against Norse York. She captures the fortress at Derby (belonging to the Five Boroughs of the Danelaw), while her brother, King Edward the Elder, takes Towcester.^[4] Æthelflæd's armies also ravage Brycheiniog (Wales) in revenge for killing the Mercian abbot Ecbryht (see 916).
Battle of Tempsford: The English army led by Edward the Elder defeats the Danish Vikings at Tempsford. They storm the fortified burh and kill King Guthrum II of East Anglia, along with the Danish Jarls Toglos and Manna.

Battle of San Esteban de Gormaz: Umayyad forces under Abi-Abda besiege the repoblación of San Esteban de Gormaz (Northern Spain). King Ordoño II of León (supported by his brother Fruela II of Asturias) allies himself with Sancho I, king of Pamplona, and defeats the Moors. Abi-Abda is captured and executed by decapitation.

September 5 – The Great Yue Kingdom, later renamed Southern Han, is founded by Liu Yan, former governor and military advisor, in Panyu (modern Guangdong) and Guangxi. Liu Yan declares himself emperor, and gives his niece Liu Hua in marriage to Wang Yanjun, a son of his rival Wang Shenzhi (Prince of Min), to cement a relationship between the two states.

^ Brain Todd Carey (2012). Road to Manzikert: Byzantine and Islamic Warfare 527–1071, pp. 78–81. ISBN 978-1-84884-215-1.
^ Lynda Garland (April 1, 2002). Byzantine Empresses: Woman and Power in Byzantium AD 527-1204. Routledge. p. 122. ISBN 9780203024812.
^ Fine, John V. A. Jr. (1991) [1983]. The Early Medieval Balkans: A Critical Survey from the Sixth to the Late Twelfth Century. Ann Arbor: University of Michigan Press. p. 150. ISBN 0-472-08149-7.
^ Walker, Ian W (2000). Mercia and the Making of England Sutton. ISBN 0-7509-2131-5.