What Is 173 CE

Overview

173 CE (Common Era) was a year during the height of the Roman Empire’s philosophical and military challenges. It occurred during the reign of Emperor Marcus Aurelius, a period marked by Stoic philosophy, frontier wars, and widespread disease. This year falls within the broader timeframe of the Pax Romana, though internal and external pressures were increasingly evident.

The Julian calendar, introduced by Julius Caesar in 46 BCE, was the standard dating system used across the Roman world. In 173 CE, the year began on a Thursday and was numbered as 'Year 926 Ab Urbe Condita' (from the founding of Rome). The Roman Empire was still the dominant power in the Mediterranean, though facing threats from Germanic tribes and Parthian forces.

• 173 CE was a common year in the Julian calendar, beginning on Thursday, and part of the 2nd century’s pivotal developments in governance and warfare.
• The Roman Empire, under Marcus Aurelius, faced ongoing military campaigns on the Danube frontier against the Marcomanni and other Germanic tribes during this period.
• Lucius Verus, co-emperor until his death in 169 CE, had previously led campaigns against the Parthians, setting the stage for Roman military presence in the East into 173 CE.
• The Antonine Plague, likely smallpox or measles, continued to impact Roman demographics, possibly reducing population by up to 10% across major cities.
• Galen of Pergamon, a leading physician, was active in Rome, advancing medical theory through dissections and writings that would influence medicine for centuries.

How It Works

Understanding 173 CE requires examining how historical dating, political leadership, and cultural developments intersected during the Roman Imperial period. This year reflects the functioning of empire, science, and religion in a pre-modern world.

• Julian Calendar: Introduced in 46 BCE, this solar calendar had a regular year of 365 days divided into 12 months, with a leap day every four years. In 173 CE, it remained the standard across Roman territories.
• Marcus Aurelius: Ruling as Roman Emperor from 161 to 180 CE, he was the last of the 'Five Good Emperors' and authored 'Meditations,' a foundational text of Stoic philosophy.
• Parthian Empire: Ruling from 247 BCE to 224 CE, it controlled much of modern-day Iran and Iraq, frequently clashing with Rome over Armenian and Mesopotamian territories.
• Antonine Plague: Brought to Rome by soldiers returning from Mesopotamia around 165 CE, it persisted into the 170s, killing an estimated 5–10 million people.
• Galen’s Medical Work: In 173 CE, Galen was likely treating gladiators and writing treatises on anatomy, using animal dissections due to Roman prohibitions on human dissection.
• Military Campaigns: The Marcomannic Wars (166–180 CE) saw Rome fighting Germanic tribes beyond the Danube, with major battles occurring in the early 170s, including possible engagements in 173 CE.

Key Comparison

This comparative table highlights how 173 CE was a period of both conflict and innovation across civilizations. While Rome and Parthia clashed geopolitically, China faced internal instability, and Mesoamerican cultures advanced astronomically. The year illustrates global diversity in governance, technology, and societal structure.

Key Facts

173 CE stands out due to its confluence of military, medical, and philosophical developments. These facts underscore the interconnectedness of ancient civilizations and the lasting impact of this era.

• Marcus Aurelius ruled alone after 169 CE and spent much of 173 CE on the Danube frontier, where Roman forces fought the Marcomanni and Quadi in harsh conditions.
• The Antonine Plague may have killed up to 2,000 people per day in Rome at its peak, weakening military recruitment and economic productivity into 173 CE.
• Galen published On the Affected Parts around this time, a detailed work on anatomy and disease that remained authoritative for over a millennium.
• The Parthian ruler Vologases IV reigned from 147 to 191 CE, engaging in intermittent warfare with Rome over control of Armenia and northern Mesopotamia.
• Roman legion deployment in 173 CE included Legio II Adiutrix stationed in Pannonia, playing a key role in defending the empire’s northeastern frontier.
• The Julian calendar had a leap year every four years without exception, leading to a slight overcorrection of 11 minutes per year, later addressed by the Gregorian reform in 1582.

Why It Matters

Studying 173 CE provides insight into the resilience and decline of empires, the spread of disease, and the evolution of scientific thought. This year exemplifies how interconnected global events were, even in antiquity.

• The Marcomannic Wars marked a turning point, as Rome faced sustained threats from Germanic tribes, foreshadowing later invasions that would destabilize the empire.
• Galen’s medical theories influenced Islamic and European medicine until the 17th century, demonstrating the long-term impact of 2nd-century scholarship.
• The Antonine Plague contributed to a demographic crisis, reducing manpower for the Roman army and economy, with effects lasting decades.
• Stoic philosophy, as practiced by Marcus Aurelius, continues to inspire modern leadership and personal development literature today.
• 173 CE highlights the importance of intercultural exchange, as trade and conflict between Rome, Parthia, and Han China shaped technological and ideological developments.

In summary, 173 CE was not an isolated year but a node in a vast network of historical forces. Its legacy endures in philosophy, medicine, and the study of empires.