Claudius struggled with various physical ailments and illnesses including tremors of the head and hands, a limp, a runny nose and foaming at the mouth. Historians have since speculated that he may have suffered from cerebral palsy or Tourette’s syndrome, but his family considered his condition a sign of weakness and a source of great public embarrassment. His own mother supposedly called him “a monstrosity of a human being, one that nature began and never finished,” and his sister is said to have prayed that Rome would never have to endure him becoming its emperor.

He later faced constant humiliation at the hands of his nephew, the Roman Emperor Caligula. According to the ancient historian Suetonius, Caligula delighted in mocking his uncle for his infirmities, and if Claudius dozed off during dinner gatherings, guests were encouraged to pelt him “with the stones of olives and dates.”

Claudius’ handicaps saw him repeatedly passed over for a chance at important public office. He was kept out of sight for most of his youth, and his royal relatives went out their way to place him far down the line of succession. Claudius’ uncle, the Emperor Tiberius, repeatedly rebuffed his requests to begin a political career, instead appointing him to low-prestige priesthoods.

Claudius abandoned his political aspirations and filled his days with drinking, gambling and womanizing until A.D. 37, when his nephew Caligula assumed the imperial purple. Caligula was inexperienced and vulnerable, and to help shore up his claim to the throne, he appointed Claudius, then almost 46 years old, as his co-consul.

When he wasn’t distracting himself with drink and games of chance, Claudius spent long hours immersed in books and academic study. Despite having been labeled a dullard by his family, he possessed a keen intellect that impressed the historian Livy, who encouraged him to take up writing.

Claudius would later produce dozens of volumes on the history of Carthage, the Etruscans, the Roman Republic and even the Roman alphabet. All of the future emperor’s works have since been lost, but they appear to have been reasonably respected in their time. The legendary Roman historian Tacitus even used Claudius’ work as a source for his own writings.

In A.D. 41, a cabal of Praetorian Guards—the sworn protectors of the Roman emperor—assassinated Caligula and brutally murdered his wife and child at the imperial palace. As the story goes, upon hearing the commotion, a frightened Claudius ran for his life and took refuge on a balcony. The Praetorians eventually found him cowering behind a curtain, but rather than killing him, they saluted him as Rome’s new emperor. Claudius’ disabilities may have given the impression that he could be easily manipulated, but once in power, he showed himself to be cleverer than previously believed.

Claudius deftly avoided a confrontation with the Roman senate, and purchased the loyalty of the Praetorian Guard with a massive 15,000-sesterce per man donative. His ailments appeared to improve after he took the throne, and he later claimed that he had only pretended to be dimwitted to protect himself. Some historians have even argued that he helped plan or was at least aware of the plot on Caligula’s life.

Upon taking power, Claudius faced rabid opposition from Rome’s senators, many of whom viewed him as a weak and illegitimate claimant to the throne. To help prove himself as a leader, he launched one of the most audacious military campaigns of the 1st century: the conquest of Britain.

In A.D. 43, he dispatched a force of 40,000 troops and several war elephants across the English Channel. The Romans had soon conquered a stronghold at modern day Colchester, and eventually succeeding in capturing the Catuvellauni tribal leader Caratacus. Claudius visited Britain during the invasion and remained for 16 days before returning to a hero’s welcome in Rome. He was later honored with a triumphal arch on the Via Flaminia that hailed him as the man who “brought barbarian peoples beyond Ocean for the first time under Rome’s sway.”

Claudius organized and attended chariot races and gladiatorial bouts religiously, often staying glued to his seat for hours at a time to avoid missing even a second of the bloodshed. He is even said to have joined in with the rest of the audience in counting aloud as gold pieces were paid to the victors.

The Emperor once staged a massive, 19,000-man mock sea battle on the Fucine Lake, but perhaps his most bizarre public spectacle came during a trip to the Roman seaport at Ostia. According to an account by Pliny the Elder, when a killer whale became stuck in the city’s harbor, Claudius had the creature ensnared in nets, “and setting out in person with the praetorian cohorts gave a show to the Roman people, soldiers showering lances from attacking ships, one of which I saw swamped by the beast’s waterspout and sunk.”

Claudius’ first betrothal was canceled after the girl’s parents endured a political disgrace, and his second bride fell ill and died on their wedding day. He would later marry four times, with each match seemingly more ill-fated than the one that preceded it. He divorced his first wife on suspicions of adultery and murder, and then called off his second marriage for political reasons.

Ancient sources describe Claudius’ third wife, Messalina, as scheming and sex obsessed. She supposedly carried out numerous affairs until A.D. 48, when she participated in a mock marriage ceremony with one of her lovers, the consul-elect Gaius Silius. Fearing that the pair planned to murder him and install Gaius on the throne, Claudius had both of them executed. The emperor swore he would never marry again, yet only a year later he wed the beautiful Agrippina, his niece. Agrippina proved even more treacherous than Messalina, and is said to have manipulated Claudius into naming her son Nero as his successor before engineering his assassination.

Ancient chroniclers say Claudius was killed after ingesting a poisonous mushroom, but they differ on certain key facts. The historian Cassius Dio claims Agrippina procured the deadly fungus from a poisoner named Locusta and served it to Claudius during a dinner at the palace. Tacitus, meanwhile, says the emperor’s food taster delivered the dish, and when it didn’t immediately work, Claudius’ doctor shoved a poison-dipped feather down his throat to finish the job.

Suetonius mentions both stories as a possibility but argues the second dose of poison was mixed with a batch of gruel. Almost all the ancients say Agrippina masterminded the plot to ensure her son Nero’s ascension to the throne. Still, some modern historians have since argued that Claudius’ death could have been an accident caused by him unknowingly eating an Amanita phalloides—a highly toxic strain of mushroom also known as “Death Cap.”