Years 640

**The 640s**
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### Overview

The 640s cover the period from 640 to 649.

### Events

#### Muslim Conquest of Persia and Surrounding Regions

* 637-651: The Muslim conquest of Persia was a prolonged process that continued throughout this decade.
* 637/638-641: Arab occupation of Upper Mesopotamia (Mosul), which became the Djezira. Djezira and Armenia depended on Damascus.

#### Arab Conquest of Egypt

* 639-642: The Arab conquest of Egypt marked a significant milestone in the expansion of Islamic territories.
* September 642: The Byzantine regime in Egypt surrendered to Muslims, solidifying Arab control over the region.

#### European Developments

* 639 or 647: Introduction of Buddhism in Tibet, with the foundation of the temple of Jokhang, the first Buddhist temple.
* Around 640-642: Pope John IV sent an abbot, Martin, to Dalmatia and Istria to redeem Christian prisoners. He traveled with the support of Croatian leaders and established the first contacts between Rome and the Croats.

#### Khazar Empire and North Caucasus

* 640-650: The Khazars beat an empire in the North Caucasus, on the lower Volga and Don after the collapse of the Göktürk khaganate.

#### Monothelism Crisis

* 640-681: The crisis of monothelism, a theological controversy that would continue for several decades.

#### Arab Conquest of Armenia

* 640-653: Beginning of the Arab conquest of Armenia, invaded by the general (640-643). The Armenians fought against the invaders.

#### Other Conflicts and Events

* 640 - Caesarea was conquered by the Byzantines from the Muslims.
* 641:
+ Battle of Lovedund - absolute victory of the Islamic forces for the Persians. The Persian Empire cannot be restored after this loss.
+ Conquest of Alexandria by Muslims.
+ Muslim army occupying areas in Egypt tries to continue its journey south into the Christian regions of Nubia, but is pursued by the stolen arch units.
* 643:
+ The Arabs occupy Kiranika.
+ Occupation of significant territories in various parts of the Sasan Empire by the Arabs.
* 644:
+ Ashkelon was conquered by the Byzantines from Muslims.
+ Conquests of Islamic forces in East Iran, Afghanistan, and Pakistan today.
* 646: Islamic progress in Khurasan, Armenia, and Asia Minor.

Note: I've kept all factual data, numbers, dates, and names intact while resolving conflicts logically. The output is structured with clean Markdown headings.