1150
Suryavarman II completes Angkor Wat
On the Cambodian plain, after about forty years of labor, the Khmer king's funerary temple was completed. Bas-reliefs unrolling for nearly half a mile showed the churning of the ocean of milk and Suryavarman reviewing his armies. It was the largest religious structure ever built. Its moat, over five kilometers in perimeter, created a cosmological diagram visible from the air, mapping the Hindu universe in water and stone.
Peter Lombard completes the Sentences
A Parisian master of theology, using Abelard's dialectical method but cautiously, assembled four books of theological opinions on every major question of the Christian faith. The Sentences would become the standard textbook every master was required to comment on for the next four centuries. Thomas Aquinas, Bonaventure, and Duns Scotus all wrote commentaries on the Sentences as the first step in their own theological careers.
Lalibela's early rock-cut churches begun
In the Ethiopian highlands, the Zagwe kings began commissioning churches carved directly down into the living basalt, their roofs level with the surrounding ground and their interiors hollowed out in the shape of cruciform basilicas. The work would continue for a generation or more. These monolithic churches, among the most remarkable architectural achievements in Africa, remain active places of worship to this day, their congregations filing into chambers hewn from solid rock.
Ghurid dynasty emerges in Afghanistan
The little mountain principality of Ghor, between Herat and Kabul, began its explosive rise under the brothers Ghiyath al-Din and Muhammad. Within a generation they would sack Ghazni, end the Ghaznavid dynasty, and launch the invasions that would plant Muslim rule in northern India. The Ghurids' sudden emergence from an obscure Afghan valley to conquer the richest prize in South Asia was one of the century's most dramatic political transformations.
Cahokia flooding and decline begins
The Mississippian city across from modern St. Louis suffered a series of floods of the Mississippi River that damaged its ceremonial plazas. Combined with worsening drought on the western prairies, the stresses began a long demographic decline that would empty the city within two centuries. Archaeological evidence suggests that deforestation of the surrounding uplands for fuel and construction worsened the flooding, creating a spiral of environmental degradation.
Tiwanaku collapse aftermath in the Andes
Across the southern Andes, the long collapse of the Tiwanaku civilization around Lake Titicaca had left a landscape of smaller chiefdoms fighting for control of llama caravans, mineral deposits, and terraced fields. The power vacuum that the Incas would later fill was still forming. These warring groups built hilltop fortresses called pukaras, their cyclopean walls testifying to an era of endemic conflict among communities that had once shared a common culture.
Paper mill established at Xativa
In Muslim-ruled Valencia, the first paper mill in western Europe began producing sheets from rags using Chinese techniques that had arrived by way of Samarkand and Baghdad. Within a century the technology would travel north of the Pyrenees and gradually displace parchment. The cheaper, lighter material would eventually make books affordable for a wider audience, helping to fuel the intellectual revolutions of the later Middle Ages.