May–June– The Crusader fleet rounds Greece and stops at Negroponte (modern-day Halkis), where the local authorities submit to Alexios Angelos. Encouraged by this, the Crusader leaders send him and several ships to extend his authority over the neighboring island of Andros. Mid-June, the Crusader fleet sails from Greece to Abydos, where it enters the Dardanelles.[2]
June 23– The Crusader fleet comes within sight of Constantinople, and enters the Bosporus. The Byzantine capital is defended by a garrison of 15,000 soldiers (including 5,000 men of the Varangian Guard), and a fleet of 20 galleys. On June 26, the Byzantine troops skirmish with the Crusader forces, who attack, without success, the cities of Chalcedon and Chrysopolis.[2][3]
July 2– Crusader leaders sail close to the city's walls in order to display the young Alexios Angelos, where they call upon the Byzantines to rise up in his favour. After rowing back and forth for a while, receiving insults and missiles, the attempt is abandoned. The Crusader leadership decides to land an invasion force north of Galata – using prevailing currents and winds.[4]
July 5– The Crusader fleet disembarks their horse transports, and barrels down upon the Byzantine defenders in a full cavalry charge. The Byzantines flee after brief combat, and retreat to the Tower of Galata, where they fortify themselves. After a bitter struggle, the Crusaders capture the tower and break the floating chain, and allow their fleet to enter the Golden Horn.[5]
Siege of Constantinople: The Crusaders, led by Boniface of Montferrat, capture Constantinople, in support of the deposed Emperor Isaac II and his son Alexios Angelos. This marks the main outcome of the Fourth Crusade.
July 11– The Crusaders take positions opposite the Palace of Blachernae on the northwest corner of the city. Their first attempts are repulsed, but on July 17 the Venetians take a section of the wall of about 25 towers, while the Varangian Guard holds off the Crusaders on the land wall, inflicting heavy casualties. The Venetians set fire to the buildings inside the Golden Horn walls, and then abandon the occupied fortifications.[6]
July 17–18– Alexios III tries to counterattack from the Gate of St. Romanus but retreats without a fight. Embarrassed, he prefers to escape and abandon his subjects, fleeing with the imperial treasure to Develtos (a fortified town on the Gulf of Burgas) in Thrace. Meanwhile, the Byzantine aristocracy restores the ex-emperor Isaac II to the imperial throne. On August 1, Alexios Angelos is crowned co-emperor as Alexios IV.[7]
August – Alexios IV announces new taxes and enrages the Orthodox Church by confiscating large quantities of Byzantine icons, many centuries old, and melts them down to produce enough silver to pay the massive debt to the Venetians. A riot breaks out in Constantinople – during which the Byzantine populace loots and burns the homes of Italian residents in the city.[8]
August 31– The Venetians rally a rabble of soldiers and storm through the walls, attacking the Mitation Mosque which results in extensive fires in Constantinople. Finally, they are fought off by the Byzantines and Muslims standing side by side. It becomes one of the most extensive urban conflagrations in European History and renders some 100,000 people homeless.[9]
August–October – Alexios IV leads a Crusader expedition (some 6,000 men) to extend his central-government control, against the fugitive Alexios III in Thrace. Meanwhile, a Crusader fleet operates in the Sea of Marmara in support of the Thracian campaign. The Crusaders seize several towns, including Adrianople, while Alexios escapes and withdraws to Macedonia.[10]
Europe
Spring – King Philip II of France invades Normandy and attacks a number of castles in the surrounding region. In April, John, King of England loses the support of his French vassals who desert him. Philip enters Rouen, leading to the eventual Treaty of Paris (1259) and unification of Normandy and France.
At Rouen, William de Braose, an English nobleman, becomes the guardian of the imprisoned 16-year-old Arthur of Brittany, designated heir to the throne of England – who is not known to be alive after April and is probably murdered by or at the orders of his uncle, King John.
August –Siege of Château Gaillard: French forces under Philip II begin the siege at Château Gaillard as part of a campaign to reconquer the continental properties of King John of England. During the winter of 1203/1204, the English under William Marshal attempt to relieve the castle.
Summer – On orders of Al-Adil I, sultan of Egypt, Muslim ships attack Crusader vessels off Cyprus. Ships from Acre retaliate this action, by capturing six Muslim ships off Acre. King Aimery of Jerusalem declares the truce void between Al-Aldil and the Crusaders, and raids Muslim territory in northern Palestine. Al-Adil responds by taking his army to the outskirts of Acre – but does not launch an assault and retires afterward. A plague breaks out in Acre and half the newly arrived Crusader army dies.[12]
First evidence that the Temple in London is extending loans to John, King of England. The sums remain small, but are often used for critical operations, such as the ransoming of the king's soldiers captured by the French.[16]
Ferris, Eleanor (1902). "The Financial Relations of the Knights Templars to the English Crown". American Historical Review. 8 (1): 1–17. doi:10.2307/1832571. JSTOR1832571.
Vannier, Jean-François (1986). "Les premiers Paléologues. Étude généalogique et prosopographique" [The First Palaiologoi. Genealogical and Prosopographical Study]. In Cheynet, Jean-Claude; Vannier, Jean-François (eds.). Études Prosopographiques[Prosopographic Studies] (in French). Paris: Publications de la Sorbonne. pp.171–172. ISBN978-2-85944-110-4.
Oram, Richard D., "The Earls and Earldom of Mar, c1150-1300", Steve Boardman and Alasdair Ross (eds.) The Exercise of Power in Medieval Scotland, c.1200-1500, (Dublin/Portland, 2003), pp.46–66
