AD 678

Siege of Constantinople (674–678)

Traditional end of the supposed 674–678 Arab siege of Constantinople

The fleet traditionally destroyed by a wonder weapon may instead have been wrecked by a storm hundreds of kilometres from Constantinople.

The traditional story

In the traditional account, the supposed 674–678 siege ended after Arab fleets failed to take Constantinople and suffered a disastrous shipwreck near Sillyon while withdrawing. Nikephoros has those fleets fighting repeated seasonal naval campaigns near the city across what he calls a seven-year war, wintering at Cyzicus.

News of that disaster, Nikephoros reports, prompted the Arab ruler to send envoys to Constantine IV and seek a tributary peace — a sworn settlement of thirty years.

Two episodes, joined later

Source-critical analysis indicates that Theophanes conflated the storm-driven wreck at Sillyon with a separate Byzantine land and naval victory in Lycia involving Greek fire. Sillyon lay on the southern Anatolian coast, not at Constantinople, and Nikephoros attributes the destruction there to storm and shipwreck rather than to fire.

Theophanes and Nikephoros both wrote more than a century after the events, synthesizing earlier and partly lost sources.

Whether there was a siege at all

Marek Jankowiak’s revision dates the first major Arab attempt on Constantinople to 667–669, led by Yazid; on that reconstruction there was no discrete 678 siege-ending engagement of the kind this entry describes. James Howard-Johnston has likewise challenged the conventional multi-year siege narrative.

So 678 is at best an approximate traditional endpoint, with no securely established autumn day for a head-on engagement.

Whatever happened did not close the question either: another major Arab siege of Constantinople followed in 717–718.

Sources

Researched 23 Aug 2026 5 sources 2 audit passes Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree; the research places it at ~0678.

What the sources leave uncertain

Whether Constantinople experienced a continuous or recurring siege in 674–678 is a major scholarly dispute.
Jankowiak redates the first major siege to 667–669. James Howard-Johnston has likewise challenged the conventional multi-year siege narrative.
Theophanes and Nikephoros wrote more than a century after the events and synthesized earlier, partly lost sources.
The year 678 is at best an approximate traditional endpoint; there is no securely established autumn day for a head-on engagement.