After murder of Commodus , 
( see picture)
in 192, there was another round of more civil war a year
of 6 emperors and would-be emperors. Pertinax,
Rome’s prefect, becomes emperor, killed 3 months
later by Praetorians; empire auctioned off by soldiers to
Didius Julianus, who soon falls to the leader of the
Danube legions, Septimius Severus, who must battle
other claimants for a while, but finally becomes
undisputed emperor. Severan Dynasty (197-235). 
Septimius (see
picture) was born in N. Africa, married a Syrian wife,
disliked Senators, relied on army and knights and
provincials. Increased size of army and made it the
gateway to the equestrian order. Told son to make first
priority the support of the army. Italy becomes almost
just another province. Made many non-Italian senators.
Tax burden on provinces and especially on lower level
aristocrats increased greatly. Son Caracalla (see picture); 
another bad emperor; cruel, gave even more to army,
lavish building program (such as his famous baths),
raised taxes more; he is best known for the fact that
he made all people citizens of Roman empire
-- perhaps to more easily tax them. Finally killed in
217.
Macrinus, the first member of the
equestrian class ( = knights) made emperor, but killed
next year. Another Severan relative put on throne, the 14
year old priest of a Syrian sun-god Elagabalus. 
Another one of
the infamous emperors, killed in 222. His cousin Severus
Alexander became emperor, but the real ruler was mother
Mamaea. Murdered after major military failures and
replaced by the general Maximinus the Thracian in 235
(see picture). ‘Barracks’ room emperors"
(235-284). About 20 emperors and many more contenders.
The average rule is about 2.5 years. Only two died of
natural causes. Some of more interesting ones: 
Philip the Arab,
emperor the year Rome celebrated its 1000th
anniversary. Gallienus, a great general who successfully
repelled major barbarian advances occurring as border
defenses disintegrated. Likewise Aurelian. Postumus
created for 15 years a separate ‘Gallic
Empire’, while for a while Zenobia from Palmyra in
Syria created an eastern Empire, until defeated by
Aurelian. Decius conducted a great persecution of
Christians. Army was becoming less and less Romanized;
emperors began to admit whole tribes of barbarians
(Goths, Alemanni, Franks especially) into the army - in
order to fight other tribes. City life declined, as the
burden of the military upon the them became intolerable.
Emperor no longer ‘princeps’ (= first citizen);
period of the ‘dominate’ where the Emperor is
clearly a ‘master’ (= dominus). Diocletian: reform and more chaos.
(284-316). Founder of late Empire. Wanted to tightly
reorganize empire, so everything and every one had its
place. New system of twice as many provinces (eventually
growing to 116), grouped into 12 dioceses, and 4
prefectures. (see below) 
He created double bureaucracy one for civilian rule, another for the military. These bureaucrats tended to try to enrich themselves, and corruption was everywhere, sapping the lifeblood of empire. To combat inflation (caused by debasement of currency) created Edit of Prices, which failed. Laws forced people in vital jobs to stay in their given occupations and to provide children to carry on their jobs. Soldiers’ sons had to become soldiers, farmers’ sons to be farmers. etc. As city life declined, vast estates, called latifundia, owned by powerful aristocrats, were the refuge for many farmers and others needing protection from the government; these coloni became virtually the noble’s property, as in later medieval manors
Another huge persecution of Christians
(begun 303). Diocletian moved capital from Milan to Nicomedia
in Greece and set up 
system of 2 Augusti, each who would rule one
half of empire, each with one Caesar, who would become
the next Augustus, this is the tetrarchy (= rule of four)
System worked well in defending the empire against
barbarians and Persians. Diocletian also surrounded the office of
emperor with elaborate ceremony, suggesting the emperor
was a god on earth, declared kinship with Jupiter.
Diocletian then abdicated to his
fortress palace in Split (in former Yugoslavia); soon the
Augusti and the Caesars were all calling themselves
emperor. Civil war won by Constantine the Great. Constantine, his sons and relatives (316-362).
Originally a worshipper of the Sun, Constantine
supposedly had vision of the cross and the message
‘in this sign you shall conquer’ right before
his great victory at the Milvian bridge. By this time Christians had near majorities in
some Eastern cities. 
Proclaimed a permanent Edit of Toleration of
Christians. Constantine. By paying for the establishment
of churches helped its growth greatly. By sponsoring
Church councils, where the bishops hammered out official
Christian doctrine was (Such as Nicean Creed, created by
Council of Nicea in 325), he helped prevent Christianity
from breaking into a large number of equally powerful
sects. Many sects and heresies: Donatists, Arians,
Pelasgians and various Gnostics were the most common.
Moved capital to Constantinople, set up the
future real split between the Eastern and Western
Empires, and the final development of the Byzantine
Empire. Increased the bureaucracy, until it was 50 times
the size it was under Caracalla! Barbarians were now in
important army positions and Constantine invited in new
barbarian tribes. Constantine’s relatives ruled and fought
each other as well as other pretenders and barbarians and
got heavily involved in the problems of Christian
doctrine and heresy. Julian the Apostate (361-3) tried to
restore paganism, but died fighting Persians. The final phase. There were more periods
of revolt and chaos. Barbarian invasions kept occurring.
Much of the time no single emperor controlled both East
and West. Increasingly the army was German (see story of
Stilicho). Theodosius was last to control both East and
West. Later his son Honorius governed the west, (western
capital in Ravenna), his son Arcadius the east; east-west
split was permanent. In 406 another vast wave of
barbarian invaders came, fleeing the Huns. In 410 Alaric
the Visagoth invaded and sacked Rome itself. The Huns
entered in 450. German/barbarian warlords were the real
power, the Western emperor a mere figurehead. In 476
Odacer deposed the last western emperor. The Byzantine
empire, its capital at Constantinople, continued until it
fell to the Turks in 1453.
In addition to grand architecture, (such
as the vast baths of Diocletian, the basilica of
Maxentius, St. Sophia in Constantinople, there was a
great codification of Roman law, Much literature was
written. Pagan literature was usually rather rhetorical,
overdone, an endless recycling of old themes (see Epithalamium)
. The real literary action was in the Christian writers,
who, in addition to apologetics, wrote vivid biographies
of saints. Generally Greco-Roman religion, which had
developed in largely in pre-historic or archaic times was
local, concerned with this life, not the next, which was
usually bad. It was largely focused on ritual and,
generally no organized doctrines or even rites. There was
little claim that anybody had the full ‘truth’.
Thus much participation in a wide variety of religions. Christianity grew up in the organized world of
the Roman empire. Christians developed an official
doctrine, and Emperors organized councils to define
doctrine and persecuted heretics. Early theologians like
St. Augustine used Greek philosophy and Roman rhetoric to
mount a vigorous attack on paganism. While it contained
some of the hope of a relationship with god and a better
afterlife of mystery religions, Christianity’s
message was more compelling than paganism, and it was
open to everybody. Its savior that was a historical
figure, not a figure in myth. Further, it created
thousands of ‘true believers’ whose dedication
and bravery even impressed non-believers. For
Christianity, the focus was not on this world, but the
future Kingdom of God; which is the main theme of
Augustine’s City of God, written to refute the
charge that the decline and sack of Rome was due to
Christians. The real city of Christians is not of this
earth. Thousands became monks who lived under a hard
discipline (see Rule of St. Benedict); earlier
many Christians bravely faced torture and execution due
to their hope of heavenly glory (see story of St.
Perpetua. ) Christianity was earlier the religion of more
sophisticated city-dwellers, who found in Christianity a
home in the vast and anonymous world of the later empire.
Plus the emperors could use a single, united Christian
doctrine as a way of unifying the empire. The structure of the Catholic Church mimicked
the structure of the later empire, with a Pope (who, like
the emperor, calls himself pontifex maximus),
bishops (like provincial governors), even dioceses. By late 4th century, Christianity
moved from a tolerated religion to one that persecuted
pagans and heretics; Theodosius outlawed pagan religion
in 392; there were frightful struggles between Christian
groups, especially with Arians and Donatists.