rtrapasso
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Joined: 9/3/2002 Status: offline
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Year 1225: English forces regain territory taken by the French last year with the exceptions of Poitou, the Limousin, and Perigord. Pope Honorious III obtains the release of Denmark's Valdemar II, who has been imprisoned by Heinrich, count of Schwerin. The pope threatens to excommunicate the Holy Roman Emperor Friederich II if the emperor does not embark on his promised crusade by August 1227. The Nicaean emperor John III Vatatzes defeats Latin forces who have supported the brothers of the late Theodore Lascaris and makes himself master of Asia Minor, but Theodore Ducas, despot of Epirus, takes Thessalonica, proclaims himself Byzantine emperor, and routs John's forces when they try to take Adrianople (see 1223; 1230). The 34th Abbasid caliph an-Nasir dies after a 45-year reign in which he has tried to unify the Islamic world politically and morally. His chief concern has been to restore the caliphate's former temporal power while the empire of the Seljuk Turks was collapsing in the east, and he has had considerable success in fighting the Persians, Turks, and, more recently, the Mongols, but in the absence of a strong successor his dynasty will not survive (see 1258). Cotton textiles are manufactured in Spain. The fabrics will compete with linen and wool (see 3000 B.C.). Work starts on the Cathedral of Saint Pierre in Beauvais, France, planned to be one of the largest of Gothic cathedrals, with a vault 45 m (148 ft) tall that would be the highest ever built. See also 1194 Construction; 1284 Construction. Mathematics Fibonacci's Liber quadratorum deals with Diophantine equations of the second degree. He observes that the roots of x 3 + 2x 2 + 10x = 20 cannot be constructed with ruler and straightedge; in modern terms, this means that irrational numbers exist beyond those discovered by Greek geometers. See also 1150 Mathematics; 1970 Mathematics.
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