This episode presents an alternate history scenario exploring what would have happened if Charlemagne, founder of the first Western European empire since Rome's fall, had successfully married Byzantine Empress Irene of Athens.

The narrator, Cody from Alternate History Hub, examines the historical context of both rulers: Charlemagne's 46-year reign and conquest of Western Europe, and Irene's capable but controversial rule over Byzantium from 780-802, including her blinding of her own son Constantine VI.

The video explores a lesser-known historical opportunity from 782, when Irene proposed betrothing Charlemagne's daughter Rotude to her son Constantine VI, which was cancelled in 787 when Charlemagne refused to send his daughter away.

The alternate timeline imagines the geopolitical consequences if this marriage alliance had succeeded, potentially uniting the Frankish and Byzantine empires and preventing major historical events like the Holy Roman Empire's foundation, the East-West Schism, and the Protestant Reformation.

Historical Context: Two Empires in 780 CE

Charlemagne ruled as a conqueror who spent half his life campaigning, described as having "all the positive traits" like a video game character with cheat codes enabled

Irene of Athens became Empress Regent in 780 for her 9-year-old son Constantine VI after her husband Leo IV died just 5 years into his reign

She stacked the council with capable eunuchs loyal to her

Reclaimed mainland Greece, restored Byzantine trade, and created numerous cultural epicenters

Later blinded her own son in the same room he was born in

The Byzantine Empire struggled after Justinian, nearly falling to Islamic forces at Constantinople in 717, then descended into civil wars over the value of icons

The Failed 782 Betrothal Proposal

In 782, after Charlemagne conquered the Kingdom of Lombardy, Irene proposed betrothing his 7-year-old daughter Rotude to Constantine VI to pacify potential threats from overlapping Frankish and Byzantine influence in Italy

The match was confirmed and anti-Byzantine attitudes in the west immediately began to dissipate

Both sides spent the next 5 years busy with rebellions and invasions from Abbasids and Saxons

In 787, when Rotude turned 13 and Irene sent for her, Charlemagne refused because "the man was really fond of his daughters and he just didn't want to depart with the dear Rotude"

Irene took Charlemagne's refusal as a grave insult and cancelled the wedding, leading to immediate negative consequences in the historical timeline

Alternate Timeline: The 787 Marriage Succeeds

If Charlemagne had sent Rotude to marry Constantine in 787, the betrothal would have been affirmed as the royal couple, with Irene still pulling strings but without the expedition to Italy

Constantine VI would have been given time to mature instead of making "numerous terrible decisions which drained the treasury and manpower" while being "impulsive, cruel, and hated by nobles and commoners alike"

The marriage would have promoted exchange of goods and ideas between the two realms, preventing major rebellions in Sicily and Anatolia that occurred in the historical timeline

Both empires faced formidable enemies: the Bulgar Khanate led by a capable warlord raiding Thrace, and Harun al-Rashid, "the most successful Abbasid caliph in history," who took the throne in 786

The 794 Charlemagne-Irene Marriage Alliance

In 794, six years after Rotude's marriage, Charlemagne's third wife passed away, creating an opportunity for a political marriage with Irene herself

In the historical timeline, Charlemagne married a German count's daughter to secure the Saxon frontier

Vikings had made their famous Lindisfarne landing in 793, starting an age that would "fundamentally shake Europe to its core"

Cordoba had sent an army 70,000 strong that same year, reaching as far as Narbonne

The royal match between Charlemagne and Irene was made in 794, with "both ambitious, both capable, both aching for the restoration of the Roman Empire"

There was no merger or personal union geopolitically, but trade and culture between Frankia and Byzantium flourished like never before, with exchange of ideas, language, military manuals, and goods

The alliance consolidated southern Italy and solved disputes over Croatia and Venice diplomatically rather than through conflict

Pope Leo III and the Holy Roman Empire That Never Was

In the historical timeline, Irene blinded Constantine in 797 and took the throne as "emperor" (not empress), leading Pope Leo III to consider the throne vacant because she was "a murderous female"

In 799, Pope Leo III was attacked by thugs who attempted to take his eyes and tongue, but was miraculously saved by Frankish agents, leading to Charlemagne's coronation as Holy Roman Emperor in 800

In the alternate timeline, Constantine VI remained a legitimate emperor, so "whatever Roman heritage Leo could bestow upon Charlemagne, his marriage to Irene did that five times over"

Instead of founding the Holy Roman Empire, Pope Leo III was simply imprisoned in 799 due to accusations including perjury and adultery

The alternate timeline prevents the foundation of the Holy Roman Empire, which in the historical timeline "eventually led to the east west schism, the crusades, the investiture controversy, and the protestant reformation"

The Disastrous 811 Bulgarian Campaign

In 802, Bulgarian Khan Krum crushed the Avar Khaganate and laid siege to the crucial fort of Serdica, slaughtering 6,000 defenders after promising safe passage

In 811, Constantine VI led 30,000 troops and 40,000 civilians on an expedition to Pliska, the Bulgarian capital, intending to raze and rebuild it in Byzantine fashion

The procession included magisters, senators, noble families, chief advisers, and Empress Rotude

Krum evacuated and burned the city, then laid a trap in the Balkan mountains

Krum's forces descended upon the imperial standard in the middle of the night, beheading the emperor, with Krum later turning "his skull into a drinking goblet"

The narrator notes this entire expedition happened in the historical timeline with Nicephorus leading instead of Constantine, making it "highly probable that this was the way it would have unfolded regardless"

The disaster killed both Irene's only son Constantine and Charlemagne's favorite daughter Rotude, creating a succession crisis since they were Irene and Leo's only child together

Reunification and the Death of Charlemagne

After Constantine's death, Byzantium openly rebelled against Charlemagne inheriting the throne, with multiple emperors crowned in Anatolia, Constantinople, and Thrace

"Struck by grief and fury," Charlemagne and Irene rallied a massive army supported by the Venetian navy and landed in Dyrrachium, with splintered Byzantines in the west quickly proclaiming them co-rulers

By 814, all resistance west of the Bosphorus was quelled, with many accepting that Charlemagne was "the only one who could defeat Krum the Fearsome" and "the best chance for the Roman Empire to be made whole once more"

In 814, both Khan Krum died from a stroke and Charlemagne succumbed to pneumonia, with Krum's son Omurtag immediately signing a 30-year truce and focusing on building projects

The entirety of Frankia and Byzantium became the rightful claim of Charlemagne's only surviving son Louis I, as his other sons Pepin, Charles, and Pepin had all died within a few years