Augustus

Augustus (63 BC–AD 14), born Gaius Octavius Thurinus, was adopted by his great uncle Julius Caesar in 44 BC, and was thenceforth known as Gaius Julius Caesar Octavianus. After his adoption, he became the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in AD 14.

Augustus in Gunpowder Empire
In an alternate where Agrippa lived a longer life, Augustus oversaw the expansion of Rome into Germany.

Augustus was succeeded by Agrippa when the first emperor died.