Europe by this date, with the last dying in Caucasus. 907: Loire Vikings overrun Brittany; Breton court flees to the England of Edward the Elder. 911: The Viking Rollo granted County of Rouen by France: official foundation of Normandy. 917 (20 August 917) the Bulgarians destroyed the Byzantine army in the Battle of Anchialus, one of the bloodiest battles in the Middle Ages. 927: official recognition of the first independent national Church in Europe, the Bulgarian Patriarchate. 927: Kingdom of England becomes a unified state. c. 936: Gorm the Old becomes the first recognized king of Denmark, and thus the Danish Monarchy is founded. 936: Alan II, with support from Æthelstan, commences the reconquest of Brittany. 955: The Battle of Lechfeld (10 August 955) sees a decisive victory for Otto I the Great, King of the Germans, over the Hungarian harka Bulcsú and the chieftains Lél (Lehel) and Súr. 966: Mieszko I, first duke of Poland, baptised a Christian. 968: Battle of Silistra between Russians and Bulgars. 985–986: The Norseman Erik the Red begins the colonisation of Greenland. 925: The medieval Croatian state becomes a unified kingdom under King Tomislav 988: Vladimir I, Prince of Kievan Rus', baptised a Christian c. 1000: Establishment of the Eastern Settlement and Western Settlement in Greenland. Second half of the 10th century: Page with David the Psalmist, from the Paris Psalter, is made. It is now kept at Bibliothéque Nationale, Paris. Late 10th or early 11th century: The Archangel Michael icon, is made. It is now kept at the Treasury of the Cathedral of Saint Mark, Venice. Oceania c. 950: Formation of the Tu'i Tonga Empire and of the Tuʻi Tonga dynasty in Tonga. Inventions, discoveries, introductions 10th century–12th century: Seated Guaryin Bodhisattva, is made during the Liao dynasty. It is now kept at The Nelson-Atkins Museum of Art, Kansas City, Missouri. Construction begins on the Brihadeeswarar Temple of India, during the reign of Rajaraja Chola I. The first pound lock is invented by the Chinese engineer Qiao Weiyo, improving the canal lock system. Fire arrows are invented by the Chinese. Earliest known occurrence in Mexico of Lost-wax casting. Three of the Four Great Books of Song are published (the last one in 1013), which were enormous Chinese encyclopedias having millions of written Chinese characters each. Hops first mentioned in connection with beer brewing. Zhang Sixun of China uses for the first time liquid