If I go onto Wikipedia, I can see an answer of when he was born. But I can't really follow the sources. How do historians know when Nero was born?
2Did you try checking Wikipedia's references in the Early Life section? How far did you trace this info?– T.E.D. ♦Dec 23, 2022 at 16:02
7"Nero was born at Antium nine months after the death of Tiberius, on the eighteenth day before the Kalends of January" - Suetonius, The Life of Nero, 6.1– Carlos MartinDec 23, 2022 at 16:35
The best way it could be determined is based on the writings of Tacitus and Suetonius.
In Tacitus annals, he provides info about the birth of Nero, and so does Suetonius, in his writing The Lives of the Caesars he says
Nero was born at Antium nine months after the death of Tiberius, on the eighteenth day before the Kalends of January, just as the sun rose.
Hope it made it clearer now!