The answer is not entirely certain: if we consider ancient Rome, the record for the longest-reigning emperor belongs to Augustus, but if we include the Byzantine Empire, the record goes to Basil II.
Being emperor in ancient Rome was far from a safe job. Many were killed by conspiracies, others fell victim to epidemics, and others were poisoned by the intrigues of the royal court, writes focus.it.
However, despite the dangers, there were rulers who stayed on the throne for decades.
Determining who had the longest reign is not so simple because it hinges on the end of the Roman Empire. It all hinges on the end of the Roman Empire: the Western Empire fell in 476 AD, but the Eastern Empire, often called the “Byzantine,” lasted until 1453, when the Ottoman Turks captured Constantinople.
Many historians today argue that the Byzantine Empire was in fact a continuation of the Roman Empire.
If that were the case, the record for longest tenure on the throne would go to Basil II.
Who was Basil II?
Basil II reigned from 976 to 1025: nearly half a century of internal civil wars and military campaigns abroad.
His nickname was “Bulgaroctonos” (“Bulgarian Killer”), recalling his most famous victories, which led the Eastern Empire to conquer all of Bulgaria.
He was not a beloved ruler, but he provided stability and power for a long time.
Theodosius II
Theodosius II ruled the Eastern Empire for 48 years (402-450). But he was proclaimed emperor as a child and remained under the influence of his courtiers until he grew up.
His current role as ruler remains debated due to his power.
August the First
If we count only the emperors who ruled with complete autonomy, the data belong to Augustus I. Rising to power after the death of Julius Caesar, he reigned from 27 BC to 14 AD, for a full 41 years.
He was a skilled political strategist, able to eliminate rivals like Mark Antony and Cleopatra, and transform Rome from a Republic into an Empire.
During his reign, he restored temples, roads, sewers, and palaces, restoring splendor to a city devastated by civil wars.
However, there were defeats: the most famous was that in the Teutoburg Forest (9 AD), where three Roman legions were destroyed by the Germans.