Roman emperor Diocletian orders the destruction of the Christian church in Nicomedia, beginning eight years of Diocletianic Persecution.

The concept of the Roman Emperor, a figure embodying immense power and influence, marked the imperial period of the Roman Empire, commencing with the pivotal granting of the title "augustus" to Octavian in 27 BC. This shift heralded a new era, moving away from the republican ideals that had long defined Rome. Throughout the empire's vast history, emperors adopted a fascinating array of titles, each carrying specific weight and meaning. When we speak of a Roman becoming "emperor" in English, it often signifies their adoption of the title augustus, and in later periods, basileus. Other significant titles included caesar, typically reserved for heirs-apparent to signify their succession, and imperator, a military honorific that underscored their role as supreme commanders. Early emperors, ever mindful of republican sensibilities, also embraced the humble-sounding princeps civitatis, or 'first citizen', a subtle way to distinguish themselves from absolute monarchs. Furthermore, emperors frequently consolidated republican titles, such as princeps senatus (leader of the Senate), consul, and the crucial religious office of pontifex maximus, demonstrating their multifaceted authority.

The bedrock of an emperor's rule lay in two critical pillars: his absolute control over the formidable Roman army and, crucially, the formal recognition bestowed upon him by the venerable Senate. An emperor's ascent to power would typically involve a proclamation by his loyal troops, an official investment with imperial titles by the Senate, or often, a combination of both to solidify his legitimacy. Initially, the empire was largely governed by a single emperor, but as the vastness and complexity of the Roman world grew, later periods saw emperors ruling alongside co-emperors, strategically dividing the empire's extensive administration between them for more effective governance.

The Emperor: Not a King, But a Ruler

A fundamental distinction within Roman political thought was the clear separation between the office of emperor and that of a king. The very first emperor, Augustus, vehemently rejected any recognition as a monarch, understanding the deep-seated Roman aversion to kingship, a sentiment rooted in the overthrow of Rome's early kings before the Republic was established. For the initial three centuries of Roman emperors, from Augustus right through to Diocletian, concerted efforts were made to publicly portray these leaders as mere "first citizens" or chief magistrates of the Republic, carefully sidestepping any association with the despised kings of Rome's distant past. However, with Diocletian's accession and his transformative tetrarchic reforms, which notably divided the imperial position into one emperor governing the West and another the East, the style of rule shifted dramatically. Emperors from this point onwards reigned in an openly monarchic fashion, no longer preserving the nominal principle of a republic. Yet, the deep-seated contrast with "kings" persisted. While imperial succession generally leaned towards hereditary lines, it was never automatic. It was always contingent on the existence of a suitable candidate who could gain acceptance from both the powerful army and the sprawling imperial bureaucracy. Thus, the principle of automatic inheritance, akin to traditional monarchies, was consciously avoided. Even after the dramatic collapse of the Western Empire, certain elements of the republican institutional framework, such as the Senate, consuls, and various magistrates, continued to be preserved, illustrating the enduring legacy of Rome's foundational political structures.

The Shifting Capital and the Twilight of the West

A monumental turning point in Roman history was the reign of Constantine the Great, who, in 330 AD, undertook the audacious decision to move the *Caput Mundi* – the "Head of the World" – from ancient Rome to a new capital, Constantinople, formerly known as Byzantium. This strategic relocation profoundly reshaped the empire's future. The Western Roman Empire, beleaguered by internal strife and relentless external pressures, eventually succumbed in the late 5th century following a series of devastating invasions of imperial territory by Germanic barbarian tribes. Romulus Augustulus is often cited as the last emperor of the West, his forced abdication in 476 serving as a symbolic end to an era. However, Julius Nepos maintained a claim to the title, a claim recognized by the Eastern Empire, until his death in 480. Following Nepos' demise, the Eastern emperor Zeno effectively abolished the administrative division of the empire, proclaiming himself the sole emperor of a reunited Roman Empire, at least in theory. The subsequent Eastern emperors, ruling from their magnificent capital of Constantinople, continued to proudly style themselves "Emperor of the Romans" (later rendered as βασιλεύς Ῥωμαίων in Greek). Modern scholarship, however, often refers to these long-reigning rulers as Byzantine emperors to distinguish them from their earlier Roman counterparts. The final chapter of this long lineage was written by Constantine XI Palaiologos, the last Roman emperor in Constantinople, who valiantly died during the tragic Fall of Constantinople to the Ottoman Empire in 1453.

The Legacy of Titles and the Problem of Two Emperors

From the reign of Heraclius in 629 AD, the "Byzantine" emperors formally adopted the monarchic title of basileus (βασιλεύς), a title that became exclusively reserved for the Roman emperor and the ruler of the rival Sasanian Empire, while other rulers were derogatorily referred to as *rēgas*. In addition to their significant pontifical office, some emperors, particularly in the earlier pagan era, were even accorded divine status after their death, a testament to their almost god-like authority. With the eventual hegemony of Christianity across the empire, the emperor's role evolved, becoming seen as God's chosen ruler on Earth, and a special protector and leader of the Christian Church. However, even in this sacred role, an emperor's authority on Church matters was, in practice, frequently subject to challenge from powerful ecclesiastical figures.

Due to the profound cultural rupture caused by the Turkish conquest of Constantinople, most Western historians generally consider Constantine XI Palaiologos as the last meaningful claimant to the title of Roman emperor. Intriguingly, from 1453 onwards, one of the titles proudly used by the Ottoman Sultans was "Caesar of Rome" (Turkish: Kayser-i Rum), a claim they maintained as part of their imperial titles until the Ottoman Empire itself dissolved in 1922. A surviving Byzantine group of claimant Roman emperors also existed in the distant Empire of Trebizond until its conquest by the Ottomans in 1461, although they had adopted a modified title since 1282.

A fascinating historical entanglement arose from the complex relationship between East and West. Eastern emperors in Constantinople had been widely recognized and accepted as legitimate Roman emperors, not only in the Eastern territories they directly ruled but also by the papacy and the Germanic kingdoms of the West. This recognition continued until the deposition of Emperor Constantine VI and the accession of Irene of Athens as Empress regnant in 797. Objecting to a woman ruling the Roman Empire in her own right, coupled with existing issues with the eastern clergy, the Papacy then controversially created a rival lineage of Roman emperors in Western Europe – the Holy Roman Emperors. These emperors presided over the Holy Roman Empire for most of the period between 800 and 1806. Crucially, these Western emperors were never acknowledged as legitimate Roman emperors by the court in Constantinople, and their coronations led to the enduring medieval political conundrum known as the "problem of two emperors," reflecting a deep schism in imperial legitimacy.

The Great Persecution: Rome's War on Christians

The Diocletianic or Great Persecution stands as the last and undeniably most severe persecution of Christians within the vast Roman Empire. This brutal campaign commenced in 303 AD when the reigning emperors – Diocletian, Maximian, Galerius, and Constantius – issued a series of sweeping edicts. These decrees systematically rescinded Christians' legal rights and demanded their compliance with traditional Roman religious practices, effectively forcing them to abandon their faith or face dire consequences. Later edicts intensified the crackdown, specifically targeting the clergy and, chillingly, demanding universal sacrifice, ordering all inhabitants of the empire to offer sacrifices to the Roman gods. The intensity of this persecution, however, varied significantly across the sprawling empire. It was notably weakest in Gaul and Britain, where only the first edict was generally applied, allowing Christians there a degree of reprieve. Conversely, the Eastern provinces experienced the full, devastating force of the persecution, suffering its most extreme brutality. The persecutory laws were eventually nullified by different emperors at different times; for instance, Galerius issued the Edict of Serdica in 311, which offered some tolerance. However, the joint Edict of Milan, issued by Constantine and Licinius in 313, is traditionally regarded as the definitive mark of the persecution's end, ushering in a new era of religious freedom.

Behind the Persecution: A Gradual Shift in Policy

Prior to Diocletian's reign, Christians had certainly been subject to intermittent local discrimination and hostility within the empire. Yet, emperors before Diocletian were generally reluctant to issue broad, empire-wide laws specifically targeting the religious group. In the 250s, under the reigns of Decius and Valerian, Roman subjects, including Christians, were compelled to offer sacrifices to Roman gods or face imprisonment and execution. However, historical evidence suggests these earlier edicts were primarily aimed at enforcing universal adherence to state religion for unity, rather than being a specific assault on Christianity itself. After Gallienus's accession in 260, these earlier laws largely fell into abeyance, leading to a period of relative peace for Christians. Diocletian's assumption of power in 284 did not immediately signal a reversal of imperial indifference towards Christianity. Instead, it heralded a gradual, insidious shift in official attitudes towards religious minorities. In the first fifteen years of his rule, Diocletian systematically purged Christians from the army, condemned Manicheans to death, and surrounded himself with prominent public opponents of Christianity. Diocletian's preference for activist government, combined with his deeply held self-image as a restorer of past Roman glory and traditional values, ominously foreshadowed the most pervasive persecution in Roman history. In the winter of 302, Galerius, a fervent persecutor, strongly urged Diocletian to initiate a general persecution of the Christians. Initially wary, Diocletian sought divine guidance from the oracle of Apollo at Didyma. The oracle's reply was interpreted as a clear endorsement of Galerius's position, leading to the fateful declaration of a general persecution on February 23, 303.

The Aftermath and Enduring Legacy

As noted, persecutory policies varied considerably in their intensity across the vast empire. While Galerius and Diocletian were ardent and ruthless persecutors, Constantius, ruling in the West, was notably unenthusiastic about the campaign. Consequently, later persecutory edicts, including the chilling calls for universal sacrifice, were never fully applied within his domain. His son, Constantine, upon taking imperial office in 306, immediately restored Christians to full legal equality and returned property that had been confiscated during the persecution. In Italy in 306, the usurper Maxentius ousted Maximian's successor Severus, explicitly promising full religious toleration to win support. Galerius finally brought an end to the persecution in the East with the Edict of Serdica in 311, but sadly, it was resumed in Egypt, Palestine, and Asia Minor by his successor, Maximinus. The truly decisive moment came with Constantine and Licinius, Severus's successor, who signed the momentous Edict of Milan in 313. This groundbreaking edict offered a far more comprehensive and robust acceptance of Christianity than Galerius's earlier decree. Later that year, Licinius ousted Maximinus, finally bringing a definitive end to the persecution in the East.

Despite the immense suffering and hardship it caused, the persecution ultimately failed to check the inexorable rise of the Church. By 324, Constantine had emerged as the sole ruler of the entire empire, and Christianity had undeniably become his favored religion, paving the way for its eventual establishment as the state religion. While the persecution tragically resulted in death, torture, imprisonment, or dislocation for many Christians, it's important to note that the majority of the empire's Christian population managed to avoid such severe punishment. However, the persecution did cause lasting rifts and schisms within many churches, dividing those who had complied with imperial authority (derisively known as the *traditores*, or "those who handed over") from those who had remained "pure" in their faith. Certain schisms, such as those of the Donatists in North Africa and the Melitians in Egypt, persisted long after the persecutions officially ended, with the Donatists not reconciling with the mainstream Church until after 411. Historians continue to debate the exact scope and barbarity of these events. Some scholars suggest that in the centuries following the persecutory era, Christians developed a "cult of the martyrs" and may have exaggerated the barbarity of the persecutions. Other historians, meticulously utilizing texts and archaeological evidence from the period, assert that this position is erroneous, arguing for the accuracy of Christian accounts. Criticism of Christian narratives, particularly regarding persecution, also emerged during the Enlightenment and subsequently, most notably from figures like Edward Gibbon. This skepticism can often be attributed to the political, anticlerical, and secular tenor prevalent in those periods. Modern historians, such as G. E. M. de Ste. Croix, have continued to engage in rigorous scholarship to determine whether Christian sources indeed exaggerated the scope of the Diocletianic persecution, but fundamental disagreements on this complex historical issue continue to this day.

Frequently Asked Questions About Roman Emperors and The Great Persecution

Who was the Roman emperor?
The Roman emperor was the supreme ruler of the Roman Empire during its imperial period, beginning with Octavian (Augustus) in 27 BC. This position evolved over centuries, wielding immense military, political, and religious authority.
When did the Roman Empire begin?
The Roman Empire, under imperial rule, traditionally began in 27 BC with the granting of the title "augustus" to Octavian, marking the end of the Roman Republic.
What were common titles used by Roman emperors?
Common titles included augustus (for the senior emperor), caesar (for heirs), imperator (a military honorific), and princeps civitatis ('first citizen'). Later Eastern emperors used basileus.
How did a Roman emperor gain legitimacy?
An emperor's legitimacy depended primarily on his control of the army and recognition by the Senate. Proclamation by troops, investment with titles by the Senate, or both, were crucial for establishing valid rule.
Did Romans consider emperors to be kings?
No, Romans explicitly considered the office of emperor to be distinct from that of a king. Early emperors, like Augustus, actively avoided the title of monarch due to historical Roman aversion to kingship, instead portraying themselves as leaders of the Republic, though later emperors ruled in a more openly monarchic style.
When did the Western Roman Empire fall?
The Western Roman Empire collapsed in the late 5th century AD, usually dated to 476 AD with the abdication of Romulus Augustulus, though claims to the title persisted until 480 AD.
Who was the last Roman emperor in Constantinople?
Constantine XI Palaiologos was the last Roman emperor in Constantinople, dying during the city's fall to the Ottoman Empire in 1453.
What was the Diocletianic Persecution?
The Diocletianic Persecution, also known as the Great Persecution, was the last and most severe persecution of Christians in the Roman Empire, beginning in 303 AD under emperors Diocletian, Maximian, Galerius, and Constantius.
When did the persecution of Christians end?
The Diocletianic Persecution ended with the Edict of Serdica in 311 by Galerius (in the East) and more comprehensively with the Edict of Milan in 313, issued by Constantine and Licinius, which granted official tolerance to Christianity throughout the empire.