451

451 in various calendars
Gregorian calendar	451; CDLI
Ab urbe condita	1204
Assyrian calendar	5201
Balinese saka calendar	372–373
Bengali calendar	−142
Berber calendar	1401
Buddhist calendar	995
Burmese calendar	−187
Byzantine calendar	5959–5960
Chinese calendar	庚寅年 (Metal Tiger); 3148 or 2941; — to —; 辛卯年 (Metal Rabbit); 3149 or 2942
Coptic calendar	167–168
Discordian calendar	1617
Ethiopian calendar	443–444
Hebrew calendar	4211–4212
Hindu calendars
- Vikram Samvat	507–508
- Shaka Samvat	372–373
- Kali Yuga	3551–3552
Holocene calendar	10451
Iranian calendar	171 BP – 170 BP
Islamic calendar	176 BH – 175 BH
Javanese calendar	336–337
Julian calendar	451; CDLI
Korean calendar	2784
Minguo calendar	1461 before ROC; 民前1461年
Nanakshahi calendar	−1017
Seleucid era	762/763 AG
Thai solar calendar	993–994
Tibetan calendar	阳金虎年; (male Iron-Tiger); 577 or 196 or −576; — to —; 阴金兔年; (female Iron-Rabbit); 578 or 197 or −575

Millennium:	1st millennium
Centuries:	4th century; 5th century ; 6th century;
Decades:	430s; 440s; 450s ; 460s; 470s;
Years:	448; 449; 450; 451 ; 452; 453; 454;

Year 451 (CDLI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Marcianus and Adelfius (or, less frequently, year 1204 Ab urbe condita). The denomination 451 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.

Events

Spring – Attila gathers his vassals—Bastarnae, Gepids, Heruls, Ostrogoths, Rugians, Scirians and Thuringians (among others), and smashes through Germany, causing widespread panic and destruction. He arrives in Belgica with an army (50,000 men) and crosses the Rhine.
April 7 – Attila's forces invade Gaul and sack Metz. The major cities of Strasbourg, Worms, Mainz, Trier, Cologne, Reims, Tournai, Cambrai, Amiens and Beauvais are destroyed by the Huns.
Eudocia, daughter of emperor Valentinian III, marries Huneric in Ravenna. The engagement serves to strengthen the alliance between the Western Roman Empire and the Vandal Kingdom.
June – Attila approaches Aurelianum (modern Orléans) and the city's inhabitants close the gates, forcing him to lay siege. After learning of the Hun invasion, Flavius Aetius (magister militum) moves quickly from Italy into Gaul, and joins forces with the Visigoth king Theodoric I.
June 20 – Battle of the Catalaunian Plains (Châlons): Attila avoids a pitched battle near Orléans and withdraws to the Catalaunian Plains (Champagne-Ardenne). The Roman coalition defeats the Huns, but Theodoric I is killed in the encounter. This is the last military victory of the Western Roman Empire.

Thorismund succeeds his father Theodoric I as king of the Visigoths. He is crowned in the capital at Toulouse, and extends the Visigothic Kingdom in Hispania.

May 26 – Battle of Vartanantz: King Yazdegerd II defeats the Armenian army (66,000 men) under their rebel leader Vartan Mamikonian on the Avarayr Plain (Armenia). Despite the loss of Mamikonian, who is killed, the Armenians consider this battle to have been a moral and religious victory, since Yazdegerd, out of respect for their efforts, allows them to remain Christian. The anniversary is a national and religious holiday.
Yazdegerd II issues an decree to abolish the Shabbat, and orders the execution of Jewish leaders, including the Exilarch.

October 8–November 1 – Council of Chalcedon, an ecumenical council of the Church: The monophysitism of Eutyches is repudiated and the Chalcedonian Definition set forth. As a result of this council, the Oriental Orthodox Churches eventually become a separate communion. More immediately, Jerusalem becomes a Patriarchate and Dioscorus of Alexandria is deposed as Patriarch of Antioch.