Gaius Caesar Augustus Germanicus (31 August 12 – 24 January 41), better known by his nickname Caligula (/kəˈlɪɡjʊlə/), was Roman emperor from AD 37 until his assassination in AD 41. He was the son of the Roman general Germanicus and Augustus' granddaughter Agrippina the Elder, members of the first ruling family of the Roman Empire. He was born two years before Tiberius was made emperor. Gaius accompanied his father, mother and siblings on campaign in Germania, at little more than four or five years old. He had been named after Gaius Julius Caesar, but his father's soldiers affectionately nicknamed him "Caligula" ('little boot'). [Wiki]

Augustus: https://www.goodreads.com/list/show/2...
Caligula: https://www.goodreads.com/list/show/2...
Nero: https://www.goodreads.com/list/show/2...
Hadrian: https://www.goodreads.com/list/show/2...
Vespasian & Flavian Dynasty [fiction only] -https://www.goodreads.com/list/show/9...