Summer – Emperor Michael VIII (Palaiologos) sends a Byzantine expeditionary force (some 3,500 men) led by his half-brother, Constantine Palaiologos, to the Peloponnese in southern Greece. The army is transported to Monemvasia on Genoese ships, while a small Byzantine fleet is sent to harass the Latin island holdings in Euboea and the Cyclades. After arriving at Monemvasia, Constantine lays siege to Lacedaemon (or Sparta), while the Byzantine fleet seizes the southern coast of Laconia.[1]
Battle of Prinitza: Constantine Palaiologos marches the Byzantine army up the rivers Eurotas and Alfeios towards the Achaean capital, Andravida. At a narrow pass at Prinitza (near Ancient Olympia) in Elis, the Byzantines are attacked by Achaean forces (some 300 horsemen) under John of Katavas, who inflict a resounding defeat upon them; many Byzantine soldiers are killed. Constantine himself barely escapes with his life, and flees with the remainder of his army to the safety of Mystras.[2][3]
Battle of Settepozzi: A Byzantine-Genoese fleet (some 50 galleys) is routed by the Venetians near Spetses in the Argolic Gulf, who capture four ships and inflict considerable casualties. Later, the Genoese that survive the battle managed to capture Chania on Crete. They receive orders to avoid direct confrontations with the Venetian fleet, but instead are engaged in raiding against the Venetian merchant convoys in the Euripus Strait.[4]
Europe
July – Scottish–Norwegian War: King Haakon IV (the Old) assembles a fleet (some 120 warships), and sets sail to defend the Hebrides, in an attempt to reassert Norwegian sovereignty over the Western Isles of Scotland. Haakon stops at the Isle of Arran – where in August negotiations are started with the 21-year-old King Alexander III. The talks are prolonged by the Scots until the autumn storms begin.[5]
December – Magnus VI (the Law-mender) succeeds his father Haakon IV (the Old) as king of Norway. The chieftains of the eastern part of Iceland become the last to pledge fealty to Magnus – bringing a more complete end to the Icelandic Commonwealth and the Age of the Sturlungs.
Mindaugas (Mendog), the only Christian king of Lithuania, is assassinated by his cousin Treniota. The country reverts to paganism and loses its status as a kingdom. Treniota usurps the throne (until 1264).
Winter – King Alfonso X (the Wise) conquers Niebla from the Moors – terminating any Muslim presence in the western region of Spain.[7]
England
Baronial forces led by Robert de Ferrers and Henry de Montfort lay siege to Worcester. The attackers finally enter the city and are allowed to sack the city, The Jewish community is also targeted by the attackers. Most of them are killed. The Worcester massacre is part of a wider campaign by allies of Simon de Montfort at the start of the Second Barons' War.[8]
Levant
April 4 – Egyptian forces led by Sultan Baibars (or Abu al-Futuh) attack Acre, there is severe fighting outside the walls, in which the seneschal, Geoffrey of Sergines, is badly wounded. Baibars is not yet ready to besiege the city and begins a major campaign to eliminate the Crusader kingdom of Jerusalem, the county of Tripoli and the principality of Antioch.[9][10]
Edward (the Lord Edward), son and heir of King Henry III, seizes £10,000, which had been deposited to the trust of the Knights Templar in London, by foreign merchants and English magnates.[11]
The Bonsignori firm gains the full market of the transfer of fiscal revenue, from the papal estates to Rome.[12]
^Bartusis, Mark C. (1997). The Late Byzantine Army: Arms and Society, 1204–1453, p. 49. Philadelphia, Pennsylvania: University of Pennsylvania Press. ISBN0-8122-1620-2.
^Bartusis, Mark C. (1977). The Late Byzantine Army: Arms and Society, 1204–1453, p. 50. Philadelphia, Pennsylvania: University of Pennsylvania Press. ISBN0-8122-1620-2.
^Longnon, Jean (1969). The Frankish States in Greece, 1204–1311, pp. 253–254. In Wolff, Robert Lee; Hazard, Harry W. (eds.). A History of the Crusades, Volume II: The Later Crusades, 1189–1311, pp. 234–275. University of Wisconsin Press. ISBN0-299-06670-3.
^Lane, Frederic Chapin (1973). Venice, A Maritime Republic, p. 77. Baltimore, Maryland: Johns Hopkins University Press. ISBN0-8018-1445-6.
^Helle, Knut (1995). Under kirke og kongemakt: 1130-1350, p. 196. Aschehougs Norgeshistorie. Vol. 3. Aschehoug. ISBN8203220312.
^McDonald, Russell Andrew (1997). The Kingdom of the Isles: Scotland's Western Seaboard, c. 100–c. 1336, p. 115. Scottish Historical Monographs, Tuckwell Press. ISBN1-898410-85-2.
^Picard, Christophe (2000). Le Portugal musulman (VIIIe-XIIIe siècle. L'Occident d'al-Andalus sous domination islamique. Paris: Maisonneuve & Larose. p. 110. ISBN2-7068-1398-9.
^Willis-Bund, J W; Page, William, eds. (1924). "The city of Worcester: Introduction and borough". A History of the County of Worcester: Volume 4. London: British History Online, pp. 376–390. Retrieved: 20 May 2018.
^Steven Runciman (1952). A History of The Crusades. Vol III: The Kingdom of Acre, p. 265. ISBN978-0241-29877-0.
^Williams, Hywel (2005). Cassell's Chronology of World History, p. 145. ISBN0-304-35730-8.
^Ferris, Eleanor (1902). "The Financial Relations of the Knights Templars to the English Crown". American Historical Review. 8 (1). doi:10.2307/1832571. JSTOR1832571.
^Catoni, Giuliano. "BONSIGNORI". Dizionario Biografico degli Italiani. Retrieved December 20, 2011.