Browse Historical Events by Month: What Happened in September?

King Olaf II of Norway is killed in the Battle of Svolder, against an alliance of the Kings of Denmark and Sweden and Olaf's enemies in Norway, leading to the temporary downfall of Christianity in Norway. More

The Battle of Svolder takes place in the North Baltic Sea, near Rugen, Germany, resulting in a decisive victory for the combined Viking fleets of Denmark and Sweden over the Norwegian fleet, solidifying Danish and Swedish control over the region. The Battle of Svolder is thought to be one of the most significant battles of the Viking Age. More

King Æthelred the Unready orders the massacre of Danes living in England, known as the St. Brice's Day massacre, as a response to a perceived Danish threat.

The Battle of Maldon occurs in Essex, England, where an English force led by Byrhtnoth is defeated by Viking raiders.

The Battle of Clontarf takes place near Dublin, Ireland, where the forces of Brian Boru, High King of Ireland, defeat the Viking forces of Dublin and their allies, although Brian Boru is killed in the battle.

The Battle of Stiklestad is fought in Norway, resulting in the death of King Olaf II Haraldsson, who would later be canonized as Saint Olaf.

The Battle of Stamford Bridge takes place in England, where King Harold II of England defeats an invading Norwegian army led by King Harald Hardrada, the Last Great Viking King Of Norway, securing his position before the Battle of Hastings.

William the Conqueror invades England after seven months of preparation for his invasion force, landing unopposed at Pevensey with about 7,000 men (including 2,000-3,000 cavalry). He quickly build fortifications at Hastings in preparation to fight the English army under the Anglo-Saxon King Harold Godwinson. The" Battle of Hastings" was fought on October 14, 1066 beginning the Norman Conquest of England. More

The Battle of Manzikert occurs in eastern Anatolia (modern-day Turkey), where the Seljuk Turks defeat the Byzantine Empire, leading to significant territorial losses for the Byzantines and opening Anatolia to Turkish conquest.

The Battle of Alnwick is fought in Northumberland, England, between Scottish and English forces, resulting in a Scottish victory and expanding their influence in northern England.

The Siege of Antioch begins during the First Crusade as Crusader forces surround the city of Antioch in present-day Turkey, initiating a prolonged siege.

The Crusaders, led by Godfrey of Bouillon, capture the city of Jerusalem from the Fatimid Caliphate, marking the conclusion of the First Crusade.

The Crusaders, led by Sigurd I of Norway, arrive in Lisbon, Portugal, and establish a temporary alliance with King Afonso I against the Moors.

The Battle of Tinchebray takes place in Normandy, France, where King Henry I of England defeats his older brother Robert Curthose, securing his control over Normandy.

The Crusader army of King Baldwin I of Jerusalem is ambushed by Muslim forces near Beirut, Lebanon, resulting in heavy losses.

The White Ship Disaster occurs off the coast of Normandy, France, when the vessel carrying the heir to the English throne, William Adelin, sinks, resulting in his death and a succession crisis in England.

Roger II is crowned King of Sicily, establishing the Kingdom of Sicily and becoming its first Norman ruler.

Pope Eugenius III declares the Second Crusade at the Council of Vézelay in France, calling for a military campaign to recapture the Holy Land from the Muslims.

The Treaty of Benevento is signed, ending the long-standing conflict between the papacy and the Kingdom of Sicily.

The Battle of Monte Porzio takes place near Rome, Italy, as forces loyal to Pope Alexander III defeat the Holy Roman Emperor Frederick I Barbarossa.