<Tr> <Td> </Td> <Td> Leo III "the Isaurian" (Λέων Γ _́ ὁ Ἴσαυρος) </Td> <Td> 25 March 717--18 June 741 </Td> <Td> Born c. 685 in Germanikeia, Commagene, he became a general . Rose in rebellion and secured the throne in spring 717 . Repelled the Second Arab Siege of Constantinople and initiated the Byzantine Iconoclasm . </Td> </Tr> <Tr> <Td> </Td> <Td> Constantine V "the Dung - named" (Κωνσταντίνος Ε _́ ὁ Κοπρώνυμος) </Td> <Td> 18 June 741--14 September 775 </Td> <Td> Born in July 718, the only son of Leo III . Co-emperor since 720, he succeeded upon his father's death . After overcoming the usurpation of Artabasdos, he continued his father's iconoclastic policies and won several victories against the Arabs and the Bulgars . He is given the surname "the Dung - named" by hostile later chroniclers . </Td> </Tr> <Tr> <Td> </Td> <Td> Artabasdos (Ἀρτάβασδος) </Td> <Td> June 741 / 742--2 November 743 </Td> <Td> General and son - in - law of Leo III, Count of the Opsician Theme . Led a revolt that secured Constantinople, but was defeated and deposed by Constantine V, who blinded and tonsured him . </Td> </Tr> <Tr> <Td> </Td> <Td> Leo IV "the Khazar" (Λέων Δ _́ ὁ Χάζαρος) </Td> <Td> 14 September 775--8 September 780 </Td> <Td> Born on 25 January 750 as the eldest son of Constantine V. Co-emperor since 751, he succeeded upon his father's death . </Td> </Tr>

How many roman emperors were there in total