Tiberius, sometimes enumerated as Tiberius IV, was the son of Emperor Justinian II and Theodora of Khazaria. He served as co-emperor of the Byzantine Empire with his father Justinian II, from 706 to 711. Both were killed in 711, when Bardanes led a rebellion which marched on Constantinople. After Tiberius' death, two different individuals impersonated him, with one, named Bashir, going on to be hosted by Hisham ibn Abd al-Malik, the Umayyad caliph, before his lie was discovered and he was crucified.

Justinian II, nicknamed "the Slit-Nosed", was the last Byzantine emperor of the Heraclian dynasty, reigning from 685 to 695 and again from 705 to 711. Like his namesake, Justinian I, Justinian II was an ambitious and passionate ruler who was keen to restore the Roman Empire to its former glories. However, he responded brutally to any opposition to his will and lacked the finesse of his father, Constantine IV. Consequently, he generated enormous opposition to his reign, resulting in his deposition in 695 in a popular uprising. He only returned to the throne in 705 with the help of a Bulgar and Slav army. His second reign was even more despotic than the first, and in 711 he was killed by mutinous soldiers.