What happened in 743? — events across the world

West Asia

Arab conquest of Armenia
642–744Greater Armenia
The Arab conquest of Armenia was a series of military campaigns launched in the mid-7th century by the Islamic polity of the Arabian Peninsula against the Byzantine-controlled region of Armenia, as part of the early Muslim conquests and the Arab–Byzantine wars.
SourcesWikipedia ↗Image: Original: Mohammad Adil ( talk ) Derivative: باسم / CC BY-SA 3.0 ↗
Rebellion of Artabasdos
741–743Asia Minor
Between 741 and 743, the Byzantine military governor Artabasdos rebelled against the recently ascended emperor Constantine V. This civil war divided the empire in Asia Minor.
SourcesWikipedia ↗
743 Caspian Gates earthquake
743
An earthquake reportedly occurred in the Caspian Gates region in 743 or 744, possibly affecting areas near present-day Derbent, Russia, or Tālesh, Iran.
SourcesWikipedia ↗

Founding of the Tang Dynasty
618–907Chang'an (Tang capital site), Xi'an, Shaanxi, China
The Tang dynasty was founded by Li Yuan in 618, replacing the Sui dynasty. It became a major unified dynasty in Chinese history, with its capital at Chang'an.
SourcesWikipedia ↗Image: Ian Kiu / CC BY-SA 3.0 ↗
Taika Reform
645–894Naniwa-kyō (Naniwa Palace site), Osaka, Japan
In 645, Emperor Kōtoku of Japan enacted the Taika Reforms, aiming to abolish clan rule and establish a centralized state modeled on Tang China, profoundly impacting Japanese history.
SourcesWikipedia ↗

Berber Revolt (740–743)
739–743al-Andalus
Between 740 and 743, during the reign of the Umayyad caliph Hisham ibn Abd al-Malik, a major Berber revolt erupted. Inspired by Kharijite preachers, the Berbers rose against heavy taxes and Arab rule, led initially by Maysara al-Matghari in Tangier. The revolt spread to the rest of the Maghreb and crossed the strait to al-Andalus.
SourcesWikipedia ↗

Outbreak of the Third Tikal–Calakmul War
720–744Guatemala City
The third major war erupted between Tikal and Calakmul, two superpowers of the Classic Maya period, reflecting the protracted struggle for hegemony.
SourcesWikipedia ↗Image: Dennis G. Jarvis / CC BY-SA 2.0 ↗

Muslim conquest of Transoxiana
673–751Transoxiana
In the 7th and 8th centuries, Arab armies of the Umayyad and Abbasid caliphates conquered Transoxiana in Central Asia. The region lies between the Syr Darya and Amu Darya rivers, covering parts of modern Uzbekistan, Tajikistan, Kazakhstan, and Kyrgyzstan.
SourcesWikipedia ↗Image: Dr. Husein Mu'nis et al. / Public domain ↗

These are known only to the century, not to the year. They are listed separately so a rough date is never mistaken for an exact one.