Year 734 (DCCXXXIV) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 734 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
|Ab urbe condita||1487|
|Balinese saka calendar||655–656|
|Chinese calendar||癸酉年 (Water Rooster)|
3430 or 3370
— to —
甲戌年 (Wood Dog)
3431 or 3371
|- Vikram Samvat||790–791|
|- Shaka Samvat||655–656|
|- Kali Yuga||3834–3835|
|Japanese calendar||Tenpyō 6|
|Minguo calendar||1178 before ROC|
|Seleucid era||1045/1046 AG|
|Thai solar calendar||1276–1277|
860 or 479 or −293
— to —
861 or 480 or −292
- Battle of the Boarn: The Franks under Charles Martel, mayor of the palace of Neustria and Austrasia, defeat the Frisians near the mouth of the River Boarn (now the Dutch province of Friesland). During the battle, the Frisian army is beaten and King Poppo is killed. The Franks gain control of the Frisian lands west of the Lauwers (Netherlands), and begin plundering the pagan sanctuaries. The Frisians become Frankish vassals, apart from the tribes living in East Frisia in present day Germany.
- Umayyad conquest of Gaul: Muslim forces under Abd al-Malik ibn Katan al-Fihri, governor (wali) of Al-Andalus (modern Spain), enter Provence and raid the Rhône Valley. The cities of Avignon, Arles, and probably Marseille are handed over by Count Maurontus, who is in rebellion against Charles Martel.
- 8 September. Frithubeorht is consecrated Bishop of Hexham.
- Jasaw Chan K'awiil I, ruler (ajaw) of Tikal (Guatemala), dies after a 52-year reign. He is succeeded by his son Yik'in Chan K'awiil, who becomes one of Tikal's most successful and expansionary rulers during the Late Classic period.
- During the Third Tikal-Calakmul War, K’ak Tiliw Chan Yopaat gives himself the title k’uhul ajaw, thus declaring Quiriguá’s independence from Copán.