What happened on July 31, 781?

Name: The oldest recorded eruption of Mt. Fuji (Traditional Japanese date: July 6, 781)
Start: 0781-07-31
End: 0781-07-31

The oldest recorded eruption of Mt. Fuji (Traditional Japanese date: July 6, 781)

771
Charlemagne becomes the sole King of the Franks after the death of his brother Carloman
Carloman I (28 June 751 – 4 December 771), German Karlmann, Karlomann, was king of the Franks from 768 until his death in 771.
772
Adrian I begins his reign as pope of the Catholic Church
The pope is the bishop of Rome and the head of the worldwide Catholic Church. He is also known as the supreme pontiff, Roman pontiff, or sovereign pontiff.
778
Willibald, Abbot of Heidenheim, dictates his pilgrimage to the Holy Land fifty years before, to nun Hugburc, who records
Willibald, Abbot of Heidenheim, dictates his pilgrimage to the Holy Land fifty years before, to nun Hugburc, who records this and biographies of Willibald and his brother - the first known English woman writer [1]

783
Asturian queen Adosinda was put in the monastery of San Juan de Pravia, where she lived out the rest of her life, to pre
Asturian queen Adosinda was put in the monastery of San Juan de Pravia, where she lived out the rest of her life, to prevent her kin from retaking the throne from Mauregatus.
786
Harun al-Rashid becomes the Abbasid caliph upon the death of his brother Al-Hadi
Abū Jaʿfar Hārūn ibn Muḥammad ar-Rashīd, or simply Hārūn ibn al-Mahdī (763 or 766 – 24 March 809), famously known as Hārūn al-Rashīd, was the fifth Abbasid caliph of the Abbasid Caliphate, reigning...
787
Second Council of Nicaea (7th ecumenical council) opens in Asia Minor in present-day İznik, Turkey
Second Council of Nicaea (7th ecumenical council) opens in Asia Minor in present-day İznik, Turkey
787
Byzantine empress Irene recovers Iconoclastic cult at Nicaea
Byzantine empress Irene recovers Iconoclastic cult at Nicaea

What happened on July 31, 781?: The oldest recorded eruption of Mt. Fuji (Traditional Japanese date: July 6, 781)