There were a lot of Emperors who made Rome great, and others who made Rome awful. But a select few were crazier than all the rest. Some of the best and a lot of the craziest came from Rome's 1st Dynasty: the Julio-Claudians. The first two emperors were the model for all future rulers: Augustus made Rome, and was one of the very greatest. His heir, Tiberius, was one of the worst and was totally nuts by the end (though definitely not the craziest of this list).
Tiberius was the son of Augustus' wife, Livia. He didn't expect to become Emperor, and his step-dad never liked him much, so after a decent career in the Legions came to an end, he was basically miserable with nothing to do. But dear old mom took care of killing every other heir to the throne so by the time Augustus finally died, Tiberius became emperor. He was in his 50s by then, and no one liked him even once he was in charge. His mom drove him nuts, and he was overwhelmed. So he did the natural thing: he left the running of his empire to his Praetorian Guard commander Sejanus, who went on to murder countless political rivals with fake treason charges and would eventually try to take the empire for himself (just barely failing). Tiberius moved to a luxurious villa on Capri, where he engaged in perverse sex acts of every description. He had naked children running through his garden, and a pool where young girls would swim and pleasure him. He was insanely paranoid and had most of his family killed off for fear they would depose him. The only relative he liked was his young nephew, Caligula, who was said to help him acquire pornography and arrange sexual entertainment. He made the even-more-insane Caligula his heir; according to the Roman historian Suetonius it was on purpose, knowing how Caligula would be even worse than he was, as his revenge against all of Rome.
Caligula, who succeeded Tiberius, was definitely on the very top of the Insane Emperors list. He was a spoiled brat from childhood who had committed incest with three of his sisters even before reaching adulthood. Ironically, when he became Emperor the Roman people were overjoyed, because Caligula's dad (Germanicus) had been a great hero and general. They figured he would bring on a new golden age after the shitty rule of Tiberius. Instead, he declared himself a living God, started having open sex with his sister as well well as many senators' wives, and blew almost all the Imperial treasury on lavish orgies in the first year of his reign. He killed his young cousin and heir, made his favorite horse into a Senator, and killed several important Roman nobles (because he claimed they plotted against him, or sometimes just for fun). He turned the imperial palace into a whorehouse, and then launched a massive military expedition, supposedly to conquer Britain, but instead he stopped at the seashore of Gaul and declared war on Neptune (god of the sea). He came back to Rome with a great "treasure", of seashells. He may have murdered his favorite sister-lover when she became pregnant, though that's historically uncertain. After less than 4 years of rule, he was finally murdered by some of his own guard.
After Caligula, Rome was ruled by Claudius, who was a geezer and a drunk but mostly sane, and for the most part did a lot of good for the Empire. But he eventually married one of his nieces and she had him poisoned so that her boy, Nero, could take over (she also killed Claudius' biological son). Nero was only 16 when he became emperor, and for a few years the Empire was ruled fairly well by his mom (who was said to be in an incestuous relationship with him to be extra-controlling) and advisers, but when he got a bit older Nero grew tired of being a figurehead and took over. He tried to have his mom secretly killed in an apparent drowning accident. She surprised everyone by surviving and swimming to shore, at which point he said "screw it" and just had her stabbed to death. After that, he went truly nuts.
You may have heard how he fiddled while Rome burned, though that's probably a myth; it's also not certain whether he actually planned the fire himself to rebuild Rome in his own image. But rebuild it he did, including a massive palace and an enormous 100ft tall statue of himself as a sun god. He blamed the fire on the Christians (then an obscure cult) and was the first Emperor to persecute them. He spent like a madman and ate himself into obesity. He kicked his pregnant wife to death, but then felt sorry about it, and tried to find someone to replace her; he finally settled on a young boy that resembled her, had the boy castrated and force him to dress as a woman, and even married him. He imagined himself the world's greatest athlete, poet, and singer, and participated in public games (shameful for someone of his class) where other athletes were forced to let him win. He'd perform music and poetry for hours and was said to have executed people who interrupted, talked or fell asleep during his performances. Finally everyone was sick of him, and the Roman senate declared him an enemy of the state when several generals revolted against him. He committed suicide before he could be captured, declaring "what an artist perishes in me"!
After the death of Nero, and a brief civil war, the great general Vespasian became emperor. He ushered in a decade of peace (the longest in Roman history) and did many great things. His son Titus was also a good and wise emperor, but he died suddenly at a young age after only a few years. Domitian, Titus' younger brother, then became Emperor.
Domitian was neither good nor competent. He was in some ways the George W. Bush of the Roman Empire: he launched a war against a neighboring kingdom called Dacia, marched his legions in (though he didn't do any of the fighting himself) and after a few months went back to Rome and declared a Triumph for himself. It was like putting up a banner saying "Mission Accomplished"; except the Dacians weren't actually beaten. Within a year the war was going very badly for the Romans, and it would actually take 20 more years to finally defeat them!
Domitian became obsessed with the goddess Minerva, convinced that she spoke to him in dreams and protected him. He persecuted Christians, stripped power from the Senate, and after a few prominent philosophers had criticized him, he had them all banned from Rome. He executed several senators and generals, and exiled his own wife. He was finally assassinated by his own butler.
After Domitian and the end of the Flavian Dynasty, Rome entered its greatest period of prosperity with what history came to call the "Five Good Emperors". Hadrian was right in the middle of that period, and he was undoubtedly a good emperor, doing tons of good works, being loved by his citizens, and considered by his contemporaries to be wise and just. But he was also more than a little crazy. He was a great believer in esoteric mysteries and astrology from an early age, in part likely due to a prophecy that claimed he'd become emperor (since he'd been adopted by the previous emperor, Trajan, that was a pretty safe bet though). He didn't really like the city of Rome very much and was the only major emperor to spend more than half his reign traveling to other parts of the Empire (something emperors didn't do much of except in times of war). Like his adopted dad, Hadrian had a predilection for young men, and on one of his travels he met and fell in love with a young teenage Greek boy of low birth named Antinous. He took the boy with him, wrote erotic poetry in his honor, and lavished favors on him. They were together for 7 years, until Antinous drowned on the river Nile (it's not clear if it was accident, suicide, or a murder arranged by people worried about how highly Hadrian was honoring him).
That was when Hadrian went nuts with grief (accounts say he 'wept like a woman', inconsolably), and then declared that Antinous was now a god! Hadrian ordered that Antinous be worshiped throughout the Empire. He also built an entire city in the boy's honor, called Antinopolis.
Incredibly, the cult of the Hadrian's now divine dead boy-toy ended up becoming hugely popular! There were dozens of temples built to Antinous throughout the empire, games held in his honor, people named their kids after him, made offerings to him and wore talismans of him, and today there are more surviving images of Antinous than of any other person in the entire Roman world other than Augustus and Hadrian himself! His cult would live on for hundreds of years after Hadrian's death. Historians today think Antinous was so popular because of how beloved Hadrian himself was, because of how beautiful Antinous was, and because of the romantic and tragic 'love story' of his origin as a god. It's one of the few cases where an Emperor going crazy turned out to be popular.
The last of the Five Good Emperors (Marcus Aurelius) was succeeded by his 18-year old son, Commodus. Aurelius had been a great philosopher-king, but unfortunately, his boy was a batshit nuts sadist (if you've watched "Gladiator", you already know a very badly-mangled version of this story). One Roman historian of the era said that "Aurelius had left behind an Empire of Gold and Commodus turned it into an Empire of iron and rust". Like Nero, Commodus fancied himself a sportsman, but rather than a regular athlete, Commodus liked to pretend to be a gladiator so he could kill people, often cripples or amputees who he'd beat to death (as well as publicly butchering hundreds of animals; at one festival he personally killed almost 200!). Like Caligula, Commodus eventually decided he was a living god, but in his case the god he thought he had become was Hercules; he even took to wearing the lion-skin cloak and carrying the club that were symbolic of that god. He executed anyone he imagined was plotting against him, which sooner or later was almost anyone who served him. He once wiped out an entire Roman family just because while they weren't traitors yet, Commodus felt they might decide to be sometime in the future!
He renamed every month of the year into one of his own names or titles, and renamed the legions "commodianae", and the senate became the "commodian senate". After terrorizing Rome for 12 years, he was finally strangled to death in his bathtub by his wrestling partner.
After Commodus, the empire was eventually taken over by the Severan Dynasty, who were bad-ass warrior-emperors from modern day Libya. When the founder of the dynasty (Septimius Severus) died, he left Rome to both his sons: Caracalla and Geta. Unfortunately, the two brothers hated each other, and Geta was a nerdy wimp while Caracalla was a brutal bully. After less than two years, Caracalla had his brother murdered by the Praetorian guard, bleeding to death in his mom's arms. He then ordered that every record of Geta's name be destroyed, made it a death-penalty offense to speak his dead brother's name, and just to be extra-careful murdered 20000 people he suspected of liking his dead brother more than him. He dressed up like Alexander the Great, and may have believed he was Alexander's reincarnation; he outlawed Aristotelian philosophers because he believed Aristotle had poisoned Alexander. He also made every single free-born male citizen of the Empire change their first name to his. He was eventually stabbed to death while urinating, by one of his own soldiers.
Following some chaos after Caracalla's murder, the Severan dynasty continued with Elagabalus, his 14-year old cousin, after the boy's grandma had bribed the Legions to turn on the commanders who'd plotted Caracalla's death. The problem was, aside from being a 14 year old boy, Elagabalus was a priest of a Syrian sun god (named Elagabal). He was nuts, that very special kind of nuts only a sex-crazed teenaged religious maniac can manage. Elagabalus declared that Jupiter was no longer chief god of Rome; instead it would now be Elagabal. He also said that from now on three of the most popular Roman goddesses would be Elagabal's lovers. He built a big temple for Elagabal, and looted all the other Roman temples to move their treasures to his new temple; and forced the Senate to attend long worship ceremonies where he danced in a frenzy for his god.
Elagabalus also married one of the Vestal Virgins, which you may guess from 'virgin' part is just about the worst thing you could do with a Vestal Virgin. Mind you, he did that more to show off how nuts he was than because of any liking for girls. Elagabalus was way more into having sex with his chariot-driver and his gym trainer. Now male-male sex was not a big deal in Rome, but only if you were the one "doing the deed" and not the one "being done to"; Elagabalus was describing himself as the 'wife' of one of these men and the 'mistress' of the other, and that was scandalous. More scandalous still when he tried to make them his assistant emperors! He also made his mom and grandma senators (something women were NOT allowed to be).
Then he started getting really crazy: he would paint his face and dress as a prostitute, and sell his body to passers by for money (and not even a lot of money)! Romans, especially the soldiers (who usually loved the Severans) were getting so outraged and 'murdery' that Elagabalus' own dear granny decided he had to go for the good of the family. She had the Praetorians kill Elagabalus and make her other grandson, 13 year old Severus Alexander, the new Emperor. Ironically, the religion of Elagabal would be revived a few years later in a much more Roman form, renamed Sol Invictus (the Unconquered Sun). It was so popular that it almost ended up beating Christianity in the new-religions contest.
After the Severans were gone, Rome fell into what historians call the Crisis of the Third Century, a period where there were 26 Emperors in just 50 years, and Rome almost collapsed completely. Aurelian was credited as the Emperor who turned it back around, honored by the Romans as "Restorer of the World". To restore the world, you have to be a little nuts.
Aurelian was born into a peasant family in what is now Serbia, and his mom might even have been a slave. He worked his way up all the ranks of the Roman Legions, which is quite a feat, especially in a time when barbarians were kicking Roman's asses in all directions. He became Emperor when the previous Emperor (who was also his former commanding officer) died. He then faced off a half-dozen other would-be Emperors and a dozen different Germanic tribes, and when he got those taken care of, set off to reconquer the eastern half of the Empire which had been occupied by the Palmyrans. But he spared one of the main rebel cities (Tyana) when the magician Apollonius (of Tyana) appeared to him in an Obi-Wan Kenobi force-ghost style vision and told him that if he spared the city he'd "conquer all" (I should mention that Apollonius had by then been dead for about 172 years, having been killed by Domitian, another crazy emperor). Aurelian obeyed ghost-Apollonius, and suddenly dozens of the Palmyran cities surrendered to him, because they were so impressed with him. He reconquered the whole east and wiped out Palmyra in just six months.
Aurelian brought back the Sol Invictus religion, which turned out to be popular this time (probably because he was a way better emperor than Elagabalus), and demanded that he be addressed as "Master and God". Romans did so, because how can you argue with the guy who saved the whole Empire from collapse and spoke to long-dead wizards? Sadly, he was murdered after only 5 years of rule, by some ambitious rivals.
After Aurelian was murdered (we assume by some kind of Roman sith-lords), his second in command Tacitus swore to avenge him. He got the Senate on his side, teamed up with Aurelian's widow, got himself crowned Emperor, declared Aurelian a god, and then hunted down and executed the guys who'd murdered his former master. He even beat back the Goths, and all this in just six months. But then he started acting all nutty, talking about how he'd start renaming the whole calendar after himself (like Commodus had done), and so he was promptly assassinated (in a surprising break from the Roman tradition of waiting until an Emperor went totally bonkers and murdered a bunch of people before finally getting around to killing him).
Carinus was the son of the popular and successful soldier-Emperor Carus, taking over for his dad after Carus died from being struck by lightning. While his dad had been alive, Carinus was a pretty good soldier himself, fighting off German invaders; but shortly after becoming Emperor, he left all that behind, went to Rome and started to party hard. He got himself nine wives, and since that wasn't enough for him started to screw senators and general's wives too. He also spent more money on the annual Roman Games in one year than had ever been spent before. Seeing where this was all going, a Roman general named Diocletian rose up against him. They fought a pitched battle, and Carinus' army won and Diocletian was forced to retreat, but right after the battle Carinus was murdered by one of the generals whose wives he had been screwing.
Diocletian was for many years thought of as one of the bad/crazy emperors because he brutally persecuted the Christians (believing them to be a major threat to the stability of the Empire). In fact, his rule stabilized the Empire after the Crisis of the Third Century and it was probably thanks to him that the Empire lasted another 150 years or so before finally collapsing. So he really wasn't a bad Emperor, but he still may have been a bit crazy. He rose up against the crazy Emperor Carinus because the god Apollo made him swear an oath to do so. Once he became emperor (being crazy-lucky, since he lost his battle with Carinus, but Carinus was murdered by one of his own generals), he became a dedicated champion of traditional Roman religion. He led huge persecutions against the Christians, but also other foreign sects (like the Manicheans). He also reinstated traditional worship of the Roman Gods. At the same time, he made a ton of administrative, political and economic reforms that stabilized the Empire.
After more than 20 years of rule, Diocletian did what must have seemed like the craziest thing any Roman Emperor had ever done: he retired. He was only Roman Emperor ever to have retired from the office (rather than the much more traditional practice of being poisoned, stabbed, or dying from decadent excesses of lifestyle). He handed off the Empire to four different regional Emperors, in the hope that having four guys in charge instead of just one would help make the Empire more stable and manageable. The Roman people loved him for how he'd fixed the Empire, and begged him to come back, but he said he'd rather spend his old age growing cabbages.
At first glance, the craziest thing Constantine seemed to have done was suddenly break with all of Roman history by making Christianity the state religion. In fact, it's not that simple; for a long time before that, Rome was already moving toward more Monotheistic religious ideas, and Christ was just one of several different "one big god of everything" models that was going around. And Constantine didn't actually make Christianity the state religion, he just made it legal and encouraged it. The REALLY crazy thing is that for most of his 30 years of rule, he wasn't actually a Christian.
After Diocletian retired, the "four regional emperors" thing turned out to be a bust, and there was another round of typical bloodshed and civil war. In the end it came down to two guys: Constantine and Maxentius. Constantine had a vision/dream where he was told "in hoc signo vinces" ("You will conquer with this sign") and he had his soldiers put a sacred sign on their shields, won the battle, and became Emperor. But we don't actually know what sign it was: Christians say it was either the cross, or the Christian Chi-Rho, but other accounts suggest it might have been a cross with a sun, the sign of Sol Invictus. Constantine did legalize Christianity, but he also patronized the Unconquered Sun religion. He might not have been sure what he believed, or he might have been a cynical politician hedging his bets with two of the most popular new religions in the Empire (Christianity was popular with the nobles and scholars, while the Sol Invictus was more popular with the soldiers, who were very important). He didn't actually ban any religion, and he declared the holy day to be Sun-day, which was more associated with Sol Invictus back then. He collected Holy Christian relics, but he also wore the Sun-ray Crown (a symbol of Sol Invictus). He didn't actually get baptized as a Christian until only a few days before he died.
Oh, he also built a whole new capital for Rome, and named it Constantinople, after himself. And he poisoned his own son and boiled his wife to death.
14. Julian the Apostate
The Emperor Julian was the last descendant of Constantine, the father of Roman Christianity. Christianity had been the religion of the emperors for the last 50 years. So Julian had to be at least a bit crazy when he said "Screw it, let's try to bring back Paganism!"
Julian had been raised Christian, but like a teenage girl who watched "The Craft" too many times, he decided that Sun-worshiping Roman Paganism's secret mystery cults and trippy philosophies was more interesting than Bible Camp. When he became Emperor, he tried to re-open all the old temples that had been shut down (and kicked out a lot of the churches that had been installed in their sites). He didn't ban Christianity but he put heavy taxes on any Roman nobleman who practiced it. Some of Julian's writings survive, and reveal that he was a nerdy type of intellectual; he was once said to have ignored chariot races he was supposed to be the guest of honor at because he was distracted by a philosopher's public speech. He didn't care about his looks or wear stylish clothes. He was a vegetarian. He would rather debate his enemies than execute them; he only ever killed two people for being Christians, and those were only because they were soldiers of his who had mocked him. Even his paganism was very nerdy: it was a lot of mystical esoteric philosophy that was very personal to him.
He also thought he was the reincarnation of Alexander the Great. This last bit of craziness might have been what led him to push forward with an invasion of Persia when the odds were against him. Now, in spite of being a nerdy weirdo, Julian was actually a pretty good general (before becoming Emperor he'd won a famous battle against the Germans where he was outnumbered 3-1), but he took a spear wound in the gut during a battle, and died painfully over several days. His pro-pagan reforms were all abolished almost immediately after his death, making Julian the last pagan Emperor of Rome.
Theodosius was among the most dangerous of crazy rulers: a religious fundamentalist maniac. Eighty years after Constantine legalized Christianity, Theodosius decided God wanted him to outlaw all non-Christian religions. Not only that, he would outlaw every type of Christianity except one: Nicene Christianity (what would be called Catholicism), which was mostly only practiced by a tiny group of mostly upper-class Christians in the core cities of the Empire. That means he illegalized the faith of something like 90% of all his subjects! He closed all the great pagan temples, allowed Christian mobs to destroy the famous Oracle of Delphi and what was left of the Library of Alexandria, and he banned the famous (but pagan) Olympic games that had existed for almost 1200 years.
Worse still, his solution to the problem of an invading army of Goth barbarians was to buy them off. In theory, he was paying them to 'protect' him and the empire. In practice, the Goths had absolutely no reason to be loyal to him or Rome; they were Christians, but one of the now-outlawed (Arian) Christians who had every reason to despise him. Worse still, the Roman people hated the Goths who had been allowed to come streaming into their territories, but Theodosius wouldn't hear of it. When the people of the city of Thessalonica revolted, Theodosius sent in the Goths and they looted and massacred 7000 people. Even the Catholic bishops were outraged, forcing the emperor to do several months of penance.
Theodosius was the last emperor of a united Roman Empire. After his death, the Empire would be divided in two (East and West). Oh, and the leader of those Goths Theodosius hired? He was a spectacular kick-ass warrior-chief named Alaric, who would go on to sack Rome.
When Theodosius died, the western part of the Empire was inherited by his 10 year old son, Honorius. Almost all of the Emperors who took the throne young were either crazy to begin with or became crazy as soon as they came to power; Honorius was no exception. He was a weird little boy disconnected from reality, and didn't get much better as he grew older. He cared more about birds than people, and let himself be manipulated by his caretakers and advisers. At first, his father had left him in the care of a half-Roman half-Barbarian general named Stilcho, who managed to hold an increasingly disastrous situation together by a series of brilliant military maneuvers (the historian Gibbons called him "the last of the Roman Generals"), and by massive bribery of barbarian tribes that had flooded Roman territory. But Stilcho was an Arian Christian, and Honorius' Catholic advisers convinced Honorius that Stilcho had to be put to death. They killed Stilcho and most of his best commanders (pretty much the last competent loyal generals Rome had left), and Stilcho's armies all defected to the Goth chief Alaric.
While the Goths were rampaging across Italy, Honorius was busy feeding his birds, banning gladiatorial games, and issuing a law that outlawed wearing pants.
Alaric realized that there was nothing left to stop him, so he went to Rome and sacked it, the first time in 800 years that the city had fallen to an invader. When Honorius' men came to tell him that "Rome has perished", the 17-year-old emperor burst into tears; but it turned out he hadn't understood. He'd named his favorite pet chicken "Rome", and thought his adviser was telling him the chicken had died. When he realized that the chicken was alive, Honorius was immediately overjoyed.
You can Find Urbanski online at @KasimirUrbanski