declared the Pope to have no jurisdiction over the Archbishop of Ravenna, since that city was the seat of the Exarch, his immediate representative. His subsequent moves in Calabria and Sardinia were marked by further strippings and request of tributes that enraged his Italian subjects. According to Warren Treadgold, the first themes were created between 659 and 661, during the reign of Constans II. Death and succession On 15 July 668, he was assassinated in his bath by his chamberlain, either killed with a bucket or stabbed with a knife. His son Constantine succeeded him as Constantine IV. A brief usurpation in Sicily by Mezezius was quickly suppressed by the new emperor. Assessments and legacy The historian Robert Hoyland asserts that Mu'awiya was a significant Islamic challenge for Constans to "deny [the divinity of] Jesus and turn to the Great God who I worship, the God of our father Abraham" and speculates that Mu'awiya's tour of Christian sites in Jerusalem was done to demonstrate "the fact that he, and not the Byzantine emperor, was now God's representative on earth". Record in Chinese sources The Chinese dynastic histories of the Old Book of Tang and New Book of Tang mention several embassies made by Fu lin (拂菻), which they equated with Daqin (the Roman Empire). These are recorded as having begun in the year 643 with an embassy sent by the king Boduoli (波多力, Constans II Pogonatos) to Emperor Taizong of Tang, bearing gifts such as red glass and green gemstones. Other contacts are reported taking place in 667, 701, and perhaps 719, sometimes through Central Asian intermediaries. These histories also record that the Arabs (Da shi 大食) sent their commander "Mo-yi" (Chinese: 摩拽伐之, Pinyin: Mó zhuāi fá zhī), to besiege the Byzantine capital, Constantinople, and forced the Byzantines to pay them tribute. This Arab commander "Mo-yi" was identified by historian Friedrich Hirth as Muawiyah I (r. 661–680), the governor of Syria before becoming the Umayyad caliph. The same books also described Constantinople in some detail as having massive granite walls and a water clock mounted with a golden statue of man. The Byzantine historian Theophylact Simocatta, writing during the reign of Heraclius (r. 610–641), relayed information about China's geography, its capital city Khubdan (Old Turkic: Khumdan, i.e. Chang'an), its current ruler Taisson whose name meant "Son of God" (Chinese: Tianzi), and correctly pointed to its reunification by the Sui Dynasty