The Imperial fleet of Japan invades Kyūshū, the third largest island of the Japanese Archipelago and most southwesterly of its four main islands, by the order of Empress Saimei.

En route, Princess Nukata composes a famous poem at Nikitatsu in the province of Iyo.

Emperor Tenji ascends to the throne of Japan after Empress Saimei's death in 661.

The rapidly expanding empire of the Arabs has penetrated as far northward as the northern Caucasus by the middle of the seventh century, and the Khazars engage in the first of a series of wars with the Arab empire.

The Arabs initially force the Khazars to abandon Derbent in 661.

Emperor Constans II, highly interested in south Italian affairs, appoints a Neapolitan named Basil dux or magister militum in 661, inaugurating the Duchy of Naples.

He has authority over the neighboring seaports of Gaeta, Amalfi, and Sorrento, though each of these is largely autonomous.

The duchy will coin monies with the effigy of the emperor and Greek inscriptions; Greek is the official language.

Aripert, who is not a warrior, spreads Catholicism over the whole Lombard realm and builds the Church of the Savior in Pavia, the capital, ending the Arianism at the court.

Orthodox Christian monasteries are established at Pavia, …

…Monza, and …

…Milan.

Mostly renowned for his church foundings, Aripert leaves the kingdom in a state of peace, asking the nobles to elect jointly his two sons, Perctarit and Godepert, which they do.

Ali, while praying in a mosque at Kufah in January 661, is struck with a poisoned sword by a Kharijite, intent on avenging the men slain at Nahrawan.

'Ali dies two days later and is buried near Kufah.

Muawiyah, ruling Syria from Damascus, seizes the caliphate leadership from Hasan, Ali’s son and successor.

The Shiites refuse to recognize Muawiyah, insisting that only members of the Prophet's clan, specifically, Hasan and Husayn, the male descendants of Muhammad's daughter Fatima and her husband Ali, could rightfully have succeeded him.

The first Muslim civil war finally ends with 'Ali's assassination in 661, but the religious split will endure between the Sunnites and the Shi'ites.

The orthodox Sunni Muslims recognize the first four caliphs as Muhammad's rightful successors, whereas the Shi'ites believe that Muslim leadership belonged to Muhammad's son-in-law, 'Ali, and his descendants alone.

Mu'awiyah, now free to establish himself as the first caliph of the Umayyad house, elevates Damascus, which had been his provincial capital, to the status of imperial capital.