Final answer:
Caligula was born in 12 CE to Germanicus and Agrippina the Elder. Germanicus was a celebrated Roman commander, and Caligula later became emperor, noted for his initial popularity followed by madness. After Caligula, his uncle Claudius took the throne.
Step-by-step explanation:
Gaius Julius Caesar Germanicus "Caligula" was born in 12 CE, the third son of the renowned military commander Germanicus and his wife, Agrippina the Elder. Germanicus was notable for commanding 8 legions and achieved a triumph for avenging a Roman defeat in Germany. Caligula's father, after his efforts in Germany, was transferred to Syria where conflict with the governor, Gnaeus Piso, ensued. Germanicus was also the adopted son of Tiberius, and part of the Julio-Claudian Dynasty. Caligula's mother Agrippina was a steadfast woman who later returned to Rome after the death of her husband and faced Piso in a politically charged atmosphere. Caligula himself, whose real name was Gaius, became Emperor after a smooth initial transition of power following Tiberius's death, although he later descended into madness. His reign began with public favor as he enacted several progressive measures but this popularity was short-lived due to his subsequent insanity. After Caligula's assassination, his uncle Claudius became the emperor, an effective leader despite his physical impairments and initial exclusion from power.