The world in 642 AD — what happened that year

17 events the sources record for this year, grouped by region.

What happened

In the eighth month of Kōgyoku's first year, the emperor prays for rain at the Minabuchi River, bowing in all four directions; rain falls for five days (Nihon Shoki (Chronicles of Japan) 日本書紀卷第廿四皇極紀 1年 단락34)
In autumn 642, Yibi Tuluo with the two tribes Chuyue and Chumi besieges Tianshan; Guo Xiaoke drives them off and, following his advantage, takes the city where Chuyue's Sheji lives, pursues to Mount Esuo, subdues the Chumi people, and returns. (Zizhi Tongjian (Comprehensive Mirror) 권196 642년 항)

Baekje general Yunchung attacked and took Daeya fortress, killing the governor Pumseok and others. (Samguk Sagi (History of the Three Kingdoms) 卷05 善德王 11年)
To avenge the defeat at Daeya, Kim Chunchu was sent to Goguryeo to ask for troops; Goguryeo detained him. (Samguk Sagi (History of the Three Kingdoms) 卷05 善德王 11年)
Yeon Gaesomun killed King Yeongnyu and set up King Bojang. (Samguk Sagi (History of the Three Kingdoms) 卷21 寶藏王上即位條)

Yazdegerd leaves the sacred fire at Merv (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Yazdegerd is defeated at Balkh and crosses the Oxus (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Sistan submits (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)

Fall of Hamadan (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Fall of Rayy (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Zurjan asks for a treaty (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
The invasion of Khurasan by al-Ahnaf (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Fall of Kerman (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)
Fall of Makran — crossing the Indus forbidden (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)

Oswald, king of Northumbria, was killed by Penda at Maserfield and buried at Bardney; his brother Oswiu succeeded him. (Anglo-Saxon Chronicle Giles/Ingram 1847 A.D. 642 항 (pg657.txt 줄 1489))
Oswald fell in battle with Penda, king of Mercia, at Maserfield. (Bede, Ecclesiastical History of the English People Bede HE 3.9)

Fall of Bab al-Abwab (Derbent) (Al-Tabari, History of the Prophets and Kings Series I tom.5 sect.1 (Arg.) [india.history.resource.86986], Annus 22)