Final answer:
Caligula, also known as Gaius, was adopted by Tiberius and became the sole emperor after Tiberius's death by voiding the will and executing the co-heir Gemellus. Caligula's rule began with promising acts of generosity but spiraled into tyranny following his illness, leading to his assassination and the accession of his uncle Claudius.
Step-by-step explanation:
Gaius, more famously known as Caligula, was adopted by his great-uncle Tiberius. When Tiberius passed away in 37 CE, he left his estate and titles not only to Caligula but also to his own grandson, Gemellus. However, Caligula quickly voided Tiberius's will, executed Gemellus, and became the sole ruler. Initially celebrated and noted for his generosity, Caligula became known for his cruelty, extravagance, and claims of divinity following a serious illness that might have contributed to his apparent insanity. His misrule led to his assassination in 41 CE by the Praetorian Guard, which paved the way for his uncle Claudius to become emperor.
Notable events during Caligula's short reign included his efforts to consolidate power, impressive construction projects, and lavish expenditures on public spectacles. His fondness for appearing in various guises, sometimes dressed as gods or in elaborate costumes, manifested his interest in theatrical self-presentation. Caligula's actions and policies, highlighted by his extraordinary personal behavior and administrative decisions, illustrate the volatility of Roman imperial succession and the significant influence of an emperor's personality on his reign.