Gyeon Hwon conquers the southwest regions and in 900 declares himself king of Hubaekje ("later Baekje"), a country meant to revive Baekje's glory.

He establishes his capital at Wansanju, today's Jeonju, and continues to expand the kingdom.

The chancellor Cui Yin, who harbors an ardent hatred for the eunuchs and who is allied with Zhu Quanzhong, is meanwhile also rising in power at the Tang court.

By 900, Emperor Zhaozong, who has come to trust Cui and who will later describe him as "faithful but trickier" (than Han Wo, the official to whom the emperor was addressing his comment) is planning with Cui to slaughter the eunuchs.

When Cui's fellow chancellor Wang Tuan urges against such action, believing the plans to be too drastic, Cui accuses Wang of being in league with the powerful eunuchs Zhu Daobi and Jing Wuxiu, who serve as the directors of palace communications.

Upon Cui's accusations, Emperor Zhaozong orders Wang, Zhu Daobi, and Jing to commit suicide, and it is said that from this point Cui became the leading figure at court, the eunuchs regarding him with anger and fear.

The eunuchs also have become fearful of Emperor Zhaozong himself, who, after returning from Hua Prefecture, is described to be depressed, alcoholic, and unpredictable in his temperament.

The four top-ranked eunuchs—Liu Jishu and Wang Zhongxian, the commanders of the Shence Armies, and Wang Yanfan and Xue Qiwo, the new directors of palace communications—begin plotting to remove him.

After an incident in winter 900 in which Emperor Zhaozong, in a drunken rage, kills several attending eunuchs and ladies in waiting, Liu Jishu leads Shence Army troops into the palace and forces Emperor Zhaozong to yield the throne to his son Li Yu the Crown Prince.

Emperor Zhaozong and his wife (Li Yu's mother) Empress He ware honored as retired emperor (Taishang Huang) and retired empress (Taishang Huanghou) but put under house arrest.

Li Yu, whose name the eunuchs change to Li Zhen, is proclaimed emperor, but the eunuchs control the court.

They want to kill Cui, but are fearful that Cui's ally Zhu Quanzhong might react violently, so they only relieve Cui from his secondary posts as the director of finances and the director of salt and iron monopolies.

The Uyghur people, who have occupied Xinjiang since their expulsion from the Mongol steppes in 840 by the Yenisey Kyrgyz, in around 900 abandon their indigenous religion—a combination of shamanistic and Buddhist traditions—for Sunni Islam.

The Magyars under Árpád and Kurszán gain full control of the Carpathian Basin by about 900.

Abdallah, son of the Aghlabid emir Ibrahim II, represses a revolt of his Muslim subjects and then initiates a campaign against the last imperial strongholds in Sicily.

The Establishment of the County of Hainaut (c. 900)

Around 900 CE, the County of Hainaut is formally established in Lotharingia, the former Middle Kingdom of the Carolingian Empire. The county’s creation is tied to Duke Reginar I of Lorraine, a powerful noble and grandson of Emperor Lothair I, who assumes the title of Count of Hainaut.

Reginar I and the Creation of Hainaut

• Reginar I (also called Reginar Longneck) had already been a dominant figure in Lotharingian politics, holding the titles of Margrave of Lotharingia and Duke of Lorraine.
• Around 900, he consolidates his rule over the region of Hainaut, taking the title Count of Hainaut, formalizing its status as a distinct feudal entity within Lotharingia.
• The county is located between the Scheldt and Meuse rivers, a strategic border region with strong military and economic importance.

Hainaut’s Role in Feudal Europe

• As Lotharingia becomes increasingly contested between East Francia and West Francia, the Counts of Hainaut gain increasing autonomy.
• Hainaut serves as a buffer zone, making it a militarily significant stronghold in the power struggles between West Francia, East Francia, and later the Holy Roman Empire.
• The county will become an important feudal domain, playing a key role in the later political landscape of medieval France and the Low Countries.

Legacy of the County of Hainaut

• Hainaut will remain a powerful regional lordship, later becoming part of the Duchy of Burgundy and the Habsburg Netherlands.
• The foundation of the county around 900 CE marks the continuing fragmentation of the Carolingian Empireand the emergence of local feudal rulers as the dominant political figures in post-Carolingian Europe.
• Reginar I’s dynasty—the House of Reginar—will remain influential in the Low Countries for generations.

The establishment of the County of Hainaut under Reginar I reflects the transition from centralized Carolingian rule to decentralized feudal governance, setting the stage for the political structure of medieval Europe.

Muhammad has been given the former palace of the Tahirids as his residence in Baghdad.

In January 900, however, the vizier Ubayd Allah ibn Sulayman ibn Wahb learns that Muhammad is planning to escape, and he is arrested.

Nothing further is known of him thereafter.

The Mezzogiorno in the time of Gregory IV of Naples is under constant Saracen assaults.

Around 900, Gregory destroys the castrum Lucullanum, a Neapolitan fortress just outside the city, to prevent the Muslims from taking it as a base.

Otherwise, he reinforces the city walls and stores supplies to ensure survival in the event of a long siege.

Louis is crowned in Forchheim on February 4, 900.

This is the earliest German royal coronation about which records are known to exist.

Louis is of a weak personal constitution, often sick, and with his young age, the reins of government are entirely in the hands of others, the nobles and bishops.

Indeed, the coronation is probably a result of the fact that there is little Louis can gain at the expense of the nobles.

Louis will also inherits Lotharingia with the death of his elder illegitimate half-brother, Zwentibold, in 900.

Al-'Abbas ibn 'Amr al-Ghanawi, who was likely born in the Diyar Mudar district of al-Jazira, had embarked on a military career in the service of the Abbasids and is first recorded as one of the officers in charge of an expedition sent against unruly Arab tribes in Iraq In the following year he had been appointed by the caliph al-Mu'tadid as governor of al-Bahrain and al-Yamamah and tasked with driving the Qarmatians led by Abu Sa'id Jannabi out of the region.

Since the Qarmatians have already successfully occupied much of al-Bahrain, including al-Qatif, al-'Abbas had assembled an army of regular soldiers, Bedouin fighters and volunteers before departing from al-Basra for the province.

Shortly after their departure, al-'Abbas and his army meet the Qarmatians and engage them in battle.

The first day of fighting ends in a standstill, but in the evening the Bedouins and volunteers abandon the campaign and return to al-Basra.

The following morning, the two armies resume fighting, and al-'Abbas's depleted forces are routed; he and seven hundred of his men are compelled to surrender.

The day after the battle, Abu Sa'id orders that the captured soldiers all be put to death; al-'Abbas alone is spared and is eventually released, with instructions to warn al-Mu'tadid of the futility in opposing the Qarmatians.

He returns to Iraq and is rewarded by al-Mu'tadid for his efforts.