The Book of Jin, an official Chinese historical text covering the history of the Jin Dynasty from 265 to 420, is compiled in China during the Tang Dynasty.

Its chief editor is the chancellor Fang Xuanling, who dies in this year as well.

Drawing mostly from official documents left from earlier archives, a few essays in volumes 1, 3, 54 and 80 have been composed by the Tang Dynasty's Emperor Taizong himself.

The contents of the Book of Jin, however, include not only the history of the Jin Dynasty, but also that of the Sixteen Kingdoms period, which was contemporaneous with the Eastern Jin Dynasty.

Tang general Ashina She'er re-establishes Tang control of Karasahr and …

…leads a military campaign against the Tarim Basin kingdom of Kucha in Xinjiang, a vassal of the Western Turkic Khaganate.

Tang emperor Taizong, applying the same tactics toward the Western Turks as he had a decade earlier against their eastern brethren, uses emissaries to sow discord among rival tribes and gain the allegiances of powerful chiefs.

From 641 to 648, the emperor has deployed his fierce cavalry against the Western Turks, driving them from their Central Asian mountain strongholds in a successful effort to prevent them from harassing the northern caravan route to the west.

The internal policy of Constans II’s government is marked by an attempt to force unity on the church, after theological disputes about the controversial question of the divine and human natures of Christ have divided the empire.

To quiet the intense controversy caused by the Monothelete doctrine, Constans issues an imperial edict in 648 forbidding the subject to be discussed.

This edict, distributed by patriarch Paul II in Constans' name, is known as the Typos.

Tang emperor Taizong had sent an embassy, laden with gifts, to Kannauj to call on the Indian king, Harsha, in 647, six years after the establishment of diplomatic relations between the Chinese court and the kingdom of Kanauj.

On arriving, the delegation discovers that the former king is dead and that a usurper, Arjuna, has seized the throne.

Arjuna appropriates the gifts and attempts to kill all the Chinese officials, but the ambassador Wang Hsuan Tze and one surviving official contrive an escape.

After making their way to Nepal, they raise a large army, bolstered by Chinese cavalry.

Wang leads this force into Kannauj, besieges and captures the capital, takes Arjuna prisoner, and marches the usurper back to the Chinese capital of Chang'an in chains.

Pope Theodore I excommunicates Paul II of Constantinople, the first Eastern Patriarch to speak out against the use in the Nicene Creed of Filioque, the phrase attributed to attributed to the Second Ecumenical Council (the First Council of Constantinople), which says that the Holy Spirit proceeds "from the Father", without additions of any kind, such as "and the Son" or "alone”.

King Cenwalh of Wessex, returning from a three-year exile in East Anglia to reclaim his kingdom, gives three thousand hides of land around Ashdown to his nephew, Cuthred, possibly sub-king of Berkshire.

Cenwahl invites bishop Birinus to establish, under his direction, the Old Minster in Winchester.

Together, they have a small stone church built.

Constans, who had not approved the election of Pope Martin as the successor to Pope Theodore I, holds to the old conception of a single Roman Empire comprising East and West: he orders the pope's arrest.