Bukhara-born Arabic scholar Muhammad Ibn Ismail al-Bukhari, after making a pilgrimage to Mecca as a teenager, had subsequently spent sixteen years traveling through Asia.

Having listened to Muslim authorities, gathering traditions and sayings of the prophet Muhammad, he had then compiled these in an “Al-Jami al-sahih,” which has become enormously influential.

Following al-Bukhari’s death on August 31, 870, his tomb at Samarkand becomes an important shrine for pilgrims.

Boris, Khan of Bulgaria, although baptized by Constantinopolitan Rite, approaches the pope with a proposal to establish an independent Bulgarian church with Roman rites.

Receiving no response, he turns back to Constantinople and in 870 achieves his goal of a Bulgarian archbishopric within the imperial sphere.

Emperor Basil, seeking to confirm his deposition of Photios, patriarch of Constantinople, convenes the Fourth Council of Constantinople in 869-870, which issues no new dogmatic decisions and whose principal action is to restore Ignatius by deposing Photi0s for usurping his ecclesiastical position.

Bulgaria is formally placed under the nominal ecclesiastical jurisdiction of the patriarch of Constantinople but receives an independent archbishopric.

This has significant results both for the Balkan principalities and for the Orthodox Church, as well as greatly strengthening imperial Greek influence in the south Slav world.

The council greatly contributes to the growing rift between the Eastern and Western churches.

(The Roman church will eventually recognize it as the eighth ecumenical council, but the Eastern church for the most part will deny its ecumenicity and continue to recognize only the first seven ecumenical councils.)

The Zanj rebels gain control of southern Iraq by June 870, capturing al-Ubullah, a seaport on the Persian Gulf, and cutting communications to Basra, a few miles downstream, then …

…seize Ahvaz in Khuzestan (southwestern Iran).

The Muslim caliphate’s Turkish military leaders, having murdered or deposed each of the three caliphs they have installed from 861, install al-Mu'tamid as caliph in 870.

Having emptied the imperial treasuries to maintain the army and the court, and now deriving scant income from the caliphate’s increasingly restive provinces, the Turks finally end their murderous rule within the caliphate and allow al-Mu'tamid to govern without interference.

Ya'qub ibn al-Layth al-Saffar captures the Tahirid city of Herat in 870.

His campaign in the Badghis region had led to the capture of Kharijites who will later form the Djash al-Shurat contingent in his army.

Ya'qub now turns his focus to the west and began attacks on Khorasan, Khuzestan, Kerman and Fars.

These attacks forces the Abbasid caliphate to recognize him as governor of Kerman.

The librarian Anastasius had been sent in 869 by Louis II, Holy Roman Emperor as envoy to Constantinople, with two men of high rank in the Frankish Empire, to negotiate a marriage between Louis's only child, Ermengard, and Leo VI the Wise (who is either the illegitimate son of Emperor Michael III or the second son of his successor, Basil I the Macedonian; his mother, Eudokia was both Michael III's mistress and Basil’s wife).

When the envoys arrived at Constantinople, the Fourth Council of Constantinople was still in session, and Anastasius, who attended the last session (February, 870), zealously defended the papal cause and was of much service to the papal legates.

On their way home the papal legates were robbed, and the "Acts" of the council were carried off.

However, they had given most of the declarations of obedience of the Greek bishops to Anastasius, who also had a copy of the "Acts", and is thus able to bring these documents to the pope.

At the pope's order, he translates the "Acts" into Latin.

The Greek originals are lost.

Louis the German works in vain after the 870 Treaty of Meersen to acquire for his son Carloman the imperial crown and Italy.