The Bosphorus is a narrow strait separating Europe from Asia, measuring only 700 yards at its narrowest point, on which Constantinople was founded by Constantine in 324 after his decisive defeat of Licinius there ended Rome's civil wars. Throughout Byzantine history it served as both a strategic lifeline and a vulnerability: crusading armies were ferried across it under Alexios I, the Venetian fleet sailed menacingly along its shores during the Fourth Crusade, and Mehmed II secured full control of the waterway by constructing a fortress on its European bank to match one already standing on the Asian side. Its geopolitical importance persisted well beyond the Byzantine period, drawing the ambitions of powers as distant as Darius the Great and, centuries later, imperial Russia.
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What each episode says
Episode 1 (1 mention)
Brownworth mentions the Bosphorus as the geographic location on which Constantine began building his new capital in 324, making it the physical setting for the birth of the Byzantine world.
“324, when Constantine started building a new capital on the Bosphorus.”
Episode 3 (1 mention)
The site of the decisive battle in which Constantine soundly defeated Licinius in 324, ending the civil wars and leaving Constantine as sole ruler of the Roman Empire.
“Constantine soundly defeated him in a decisive battle on the banks of the Bosphorus, and,”
Episode 10 (1 mention)
“the water, and refused to cross the Bosphorus.”
Episode 11 (1 mention)
“was returned to the Bosphorus, nothing seemed able to stem the Muslim tide.”
Episode 14 (2 mentions)
The strait across which Alexios ferried Peter the Hermit's crusading mob to get them out of Constantinople and away from the city. Later used to ferry all the armies of the First Crusade across and out of harm's way after each leader had sworn the oath to Alexios.
“Alexius put them under heavy guard and ferried them all across the Bosphorus, warning Peter”
“sigh of relief as the last transport crossed the Bosphorus.”
Episode 15 (2 mentions)
The strait on which Constantinople sits, into which Andronicus threw the strangled body of Alexius II. The Venetian fleet also sailed under the walls along the Bosphorus to astonish the citizens of Constantinople.
“Venetian ships returned to ply the waters of the Bosphorus, their trading privileges restored,”
“he had Alexius strangled and threw the body into the Bosphorus.”
Episode 16 (2 mentions)
The strategic waterway separating Europe from Asia, which Brownworth notes is only 700 yards wide at its narrowest point — recognized as a key crossing point since the time of Darius the Great. Mehmed's construction of the Throat Cutter fortress on the European side to match his grandfather's fortress on the Asian side gave him full control of the strait.
“At its narrowest point, the Bosphorus separates Asia from Europe by only 700 yards, and it”
“He now could cut off all trade on the Bosphorus, and he announced that all ships must stop”
Episode 17 (1 mention)
Brownworth describes the Russians as 'beckoned by the pull of the Bosphorus,' having fallen under the spell of Byzantium in the tenth century, and nearly succeeding in conquering Constantinople before World War I reshuffled the map.
“Beckoned by the pull of the Bosphorus”
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