The time period from around 900 CE to 1100 CE was an eventful one.
Austronesian mariners had reached their greatest extent having established their civilization as far as Easter Island (ca. 700 CE-1100 CE), New Zealand (some argue for dates as late as 1250 CE), Hawaii and Madagascar (ca. 350-1000 CE) (in the case of Madagascar together with people who were genetically similar to East African Bantus), and introduced a few South American crops like the kumara to Oceania (reaching the Cook Islands by 1000 CE). Hawaii was first inhabited by Austronesian peoples ca. 300 CE, but around 1000 CE, immigrants from Tahiti called the Pa'ao, introduces a new dynasty of high chiefs, the Kapu system (a comprehensive set of strict religious laws), human sacrifce and the building of heiaus (temples).
The Tang dynasty and intermediate Five Dynasties and Ten Kingdoms Period gave way to the Song Dynasty (begun in 960 CE) in China. The Song dynasty ruled all of China until 1127 CE after which it ruled Southern China until 1279 CE. The Song dynasty was marked by a massive central state bureaucracy with posts filled on the basis of civil service exams that rivaled the former Roman Empire and contemporary Islamic empires in scope, but surpassed them in the modernity of its bureaucratic state.
The boundaries of modern Islamic South Asia were established, the Gypsies began their wanderings, and the linguistically Dravidian Brahui people migrated to Pakistan from Southern India.
Hindu Tagalog peoples created a sphere of cultural influence that reached from Hindu Middle Kingdoms in India to the Phillipines. In Vietnam, the Hindu Kingdom of Champa (ca. 7th century CE to 1471 CE) flourished with significant cultural influence from India. Cambodia's Khmer Kingdom (with its capitol at Angkor Wat) was also a Hindu Kingdom at the time (some later Kings would adopt Buddhism) and would enter its "Golden Age" around 1147 CE. Thailand was ruled by a variety of Dvaravati principalities which were client states of the Khmer Kingdoms loosely allied with each other in a manner not dissimilar to the contemporaneous Holy Roman Empire in Europe. In Western Java, the Hindu Sunda Kingdom (669 CE to 1579 CE) was in its heyday. The Medang Kingdom in Eastern Java vacillated between Hindu and Buddhist influences. In the end, of course, Buddhist replaced Hinduism almost everywhere in Southeast Asia and East Asia. The strong Hindu influences that persisted on the island of Bali in Indonesia are the only successors to this once far flung sphere of Hindu influence (similarly, the Mongolian Empire that rose and fell during Mongolia's late Middle Ages, a few centuries later, has left very little trace of its once vast Asian empire, linguistically or in modern institutions).
Around the same time, the city-state of Srivijaya in Sumatra, Indonesia, was a center of Buddhist expansion (another religion with its origins in India) in Southeast Asia and East Asia, which give rise to several Buddhist kingdoms (Kantoli, Srivijaya, Malyu, Pannai and Dharmasraya) that ultimately controlled all of Sumata within the framework of a larger Srivijaya empire. But, this empire was fading around 1000 CE because improved maritime technology allowed ships to skip intermediate ports, and because the Chola state in Southern India attacked Srivijaya's distant city-state holdings. These kingdoms were hubs of maritime trade between India, China and Southeast Asia.
In the Mediterranean, the First Crusade, launched by the Pope in 1099 CE, established short lived Christian states in the Levant, Moors were expelled from Northern Iberia from ca. 1000 CE to 1099 CE (reaching Toledo in 1085 CE). Norman soldiers routed the Moors from Southern Italy. Malta acquired its Semitic language at the time. And, conquering Seljuk Turks made Turkey, Turkish speaking and had a roughly 8% population genetic impact on the region. At its peak in 1092 CE, the Seljuk empire included almost all of the Levant, Asia Minor, the Fertile Crescent, the Southern Persian Gulf coast, the Southern Caucasus Mountain region, Iran, Afghanistan, and much of Central Asia.
This time period brought about the ethnogenesis of the Druze people of the Levant (ca. 1014 CE to 1043 CE after which they ceased trying to convert newcomers to their faith and turned inward), who may have been refugees from the arrival of the Turks in Iberia. The linguistically Uralic Hungarian language dynasty consolidated their control over Hungary and converted to Christianity (in 1001 CE); their migration to Hungary was likely driven by Turkish expansion. The Roman Catholic and Orthodox Christian churches finally formally split (ca. 1053-1054 CE), more than five hundred years after the fall of Rome.
Europe's last hunter-gatherers finally converted to farming and herding. The Holy Roman Empire, formed in 962 CE, was a loose alliance of principalities including most of modern Northern Italy and Germany. The Normans conquered England in 1066 CE. The Viking sailors settled Iceland established one of the first parliaments, the Althing, in 930 CE, and under Lief Erickson, the Vikings established a short lived North American colony of Vinland.
Relict animist refugees from the Islamization of Northern Africa and the Sahel led to the ethnogenesis of the astronomy practicing Dogon people in defensible cliff dwellings on the banks of the Niger River in Mali. The Bantu expansion in sub-Saharan Africa reached its greatest extent in Southern Africa and would remain secure there through the present.
In the New World, the proto-Inuit Thule people entered North America from Siberia (ca. 500 CE to 1000 CE), possibly sharing a common origin with the expansion of linguistically Uralic people to the West. Some of the Na-Dene people migrated to the American Southwest ca. 1000 CE, giving rise to the Navajo among others, pushed by incoming Inuits and pulled by a power vacuum in the Southwest. Mayan civilization collapsed ca. 950 CE as a result of an extreme drought. The Uto-Aztec language speaking Utes, possible pushed there by the outflows of people from the collapse of the Mayan civilization refugees then replaced the Great Basin's Fremont peoples. The Anasazi people in modern Arizona centered around a religious center a Chaco, developed a culture known for its sophisticated irrigation systems, its precision astronomy, its architecture that led to a baby boom unprecedented in history. The Mississippian culture with a capitol near modern Saint Louis attained regional population densities rivaling modern cities and had a sphere of cultural influence that extended throughout the Mississippi river basin and into the American Southwest as far as the Atlantic Coast of North Carolina.
The Cañari people of Ecuador, a small, but advanced civilization, flourished after the fall of the Mayans and before the rise of the Inca and Aztec cultures. And, in modern Acre State, Brazil, deep in the modern Amazonian rain forest, a culture that made massive geoglyphs fully visible only from thousands of feet in the air was in its prime, following in the footsteps of the Nazca Line culture of Peru, and the subsequent Andean Tiwanaku culture which also made geoglyphs.
This global ferment was driven in part by climate, the Medieval Warm Period from ca. 950 CE to 1250 CE. Arab astronomers, astronomers attached to the Song Dynasty Court in China, and astronomers in Chaco were witness to a very bright supernova in 1006 CE, to the supernova that created the Crab Nebula on the 4th of July in 1054 CE, and to Halley's Comet in 1066 CE.