# Year 536: The Volcanoes That Darkened the Sun

*History & War · Eleanor Hartwell · 2026-10-19*

## TL;DR

In the Year 536, volcanic eruptions threw ash into the atmosphere and sunlight dimmed across much of the Northern Hemisphere for months. Temperatures fell, harvests failed, and famine spread through Europe, the Mediterranean, and Asia. Historians now call it one of the worst years to be alive.

## Key facts

- Written accounts from the Mediterranean describe the sun appearing dim and shadowless for roughly a year beginning in 536.
- Tree-ring and ice-core evidence points to major volcanic activity in the mid-530s, with a second eruption a few years later.
- Crop failures and grain shortages are recorded across Europe, the Mediterranean, and parts of Asia during the same period.
- The claim that the emperor Justinian I banned cannibalism by law in 537 is rated false. He took the throne in 527, and no well-established 537 law on cannibalism is tied to this crisis.
- The cold and hunger years preceded the Justinianic plague, which struck the Mediterranean world in the 540s.

## The Year 536: When the Sun Went Dim

Say "Dark Ages" and most of us picture the medieval centuries, roughly 800 to 1400: plague, poverty, endless war. The Year 536 sits well before all of that, and it may have been worse. From the first months of 536 into late 537, roughly twenty months, much of the Northern Hemisphere lived under a strange, dimmed sky. The sun came up, but it barely seemed to do its job.

Picture the light. Byzantine historian Procopius, writing about a year of the crisis, described the sun giving off no brightness at all, shining faintly like the moon. That is not poetic exaggeration for its own sake. Tree rings and ice cores from the period point to an aerosol veil that thinned the sunlight for something like one to two years. Crops failed. Harvests shrank. And when the harvest fails, everything that depends on bread fails too.

Temperatures dropped. Later chronicles tell of Constantinople, today's Istanbul, enduring a snowstorm that dragged on for three days in the middle of summer, though that specific scene is not securely attested in contemporary sources. The cold was not just a local oddity either. Climatic anomalies show up in China and across the Mediterranean, though the popular claim that Europe was worse off still is an overgeneralization. Regions that today we call Ireland, Germany and France are said to have given the era a bleak nickname, "times of the bad breads," a phrase that appears in some later chronicle traditions but is not reliably documented for those places as a group.

Writers have reached for dramatic explanations. One popular version pins the whole thing on the volcanoes Krakatoa and Ilopango erupting five months apart. The science does not line up with that tidy story. Researchers tie the 536 volcanic winter to a major eruption, likely at a high latitude or in the tropics, rather than to that pairing. The veil it threw up was real. The neat two-volcano story is not.

What remains is the human picture. A world that went gray, a growing season that stalled, and a hunger that would push people past the edges of what we like to think humans do. That hunger is where this story goes next.

## Two Volcanoes, Five Months Apart, or Was It?

The story you usually hear blames two volcanoes for the whole Year 536 crisis: Krakatoa and Ilopango, said to have blown five months apart and thrown up a dust veil that smothered the planet. Modern research does not back that pairing. The eruption behind the 536 volcanic winter is generally placed at a high latitude, or possibly somewhere in the tropics, and it was not those two mountains firing in sequence.

That correction matters because the popular version is neater than real geology ever is. Two eruptions, five months apart, one convenient timeline. The ice cores and tree rings tell a messier story, and a more interesting one.

What the physical evidence does support is an aerosol veil hanging in the atmosphere for roughly one to two years. Note the wording carefully. An aerosol veil is not the same as a thick blanket of dust laid evenly over every country on Earth, and the popular image of the whole world sealed under a two-year dust layer overstates what the samples show.

So picture the sky not as a lid clamped down, but as a haze that wouldn't clear. Sunlight came through thinner, paler, less warm, month after month. Crops felt it before anyone wrote it down.

The popular telling makes a second leap here too, linking the dimming to a single cause with a clean date. The honest reading of the evidence points to volcanic forcing behind the cooling, with the exact culprit still argued over by researchers who study the ice. The Year 536 remains a real and brutal episode. The two-volcano explanation is the part that does not survive the check.

## Famine, Cannibalism, and Procopius's Diary

When the harvests failed in the Year 536, hunger did the rest. Small towns were raided by larger towns for no greater prize than a little more wheat, and the raiders were often just as hungry as the people they robbed.

Then the stories turn darker, and the documentary trail gets shakier. One popular version says feudal kings in the north chose one poor person each day to fill their own bellies, then tossed the leftover bones back to the poor, who may well have included the victim's own wife or children. Treat that scene as folklore. It has the shape of a legend passed around a fire, not a practice recorded in reliable records.

The Byzantine historian Procopius is the witness people quote most. He does describe the Sun giving no brightness for about a year, hanging dull and pale like the Moon. The famous line, though, the one about entering the 18th month with the Sun still lighting the Earth only as much as the Moon, is not a verified verbatim entry from any diary. It is the vivid version of what he observed, polished by retelling.

### What the records actually say about Justinian and Rome

Contrary to the popular version, Justinian I did not ban cannibalism by law in 537 "as soon as he became emperor." He took the throne in 527, a decade earlier, and no well-established 537 law aimed specifically at cannibalism is tied to this crisis.

Rome in early 537 was a city under Ostrogothic siege, and famine there is recorded. The detail that hungry Romans looted the imperial stables is reported in the original account, but it is not securely attested. What survives with confidence is the picture: a city cut off, its people desperate, and no emperor or soldier able to stop them.

## Rickets, Baldness, and a Broken Economy

Here is where the story of the Year 536 gets loudest, and where it gets shakiest. The popular version says that for 18 months humanity had no sunlight at all, and that vitamin D deficiency then hollowed out people's bones. The evidence points to dimmed sunlight, not absent sunlight, and widespread vitamin D deficiency across the population is not a measured historical fact. So treat the bodily-toll chapter as vivid storytelling, not a medical record.

Take the famous image of a healthy man swinging down off his horse and snapping his leg on the landing. It is a striking picture of a fragile, sun-starved people, and it is exactly the kind of detail that travels well in retellings. It is also undocumented. There is no reliable source that pins such an injury to this period. The same caution applies to the grimmest claim of all, that disabled people were killed and regarded as food by the able-bodied. Later chronicles do describe famine cannibalism in some stricken regions, but the specific horror of the disabled being hunted and eaten is not reliably attested.

Then there is the arithmetic that simply falls apart. You may have read that baldness spread and that 8 out of every 10 babies arrived with rickets. No record and no skeletal evidence supports that figure. It has the shape of a statistic without the substance of one. The same goes for the idea that people turned their backs on gold and emeralds, with wages paid out in wheat, eggs, and dried meat. Payment in kind and barter did happen in some famine-hit areas, so a kernel of truth sits underneath. But the sweeping claim, that precious metal and gemstones lost all value and food became the universal currency, is not established.

What survives is a picture of an economy under brutal strain, told in fragments that later storytellers stitched into something tidier and more absolute than the sources allow. The hunger was real enough in places. The tidy numbers are not.

## The Population Number That Doesn't Add Up

One line in the popular telling of the Year 536 tends to stop readers cold: world population reportedly sat at about 190 million in 535 and then collapsed to roughly 100 million by 537. That works out to a loss of nearly half of all human beings on Earth in barely two years, and it does not survive a close look.

No credible demographic record supports a crash of that size on that timeline. Plague, famine and volcanic cooling did real damage across the Northern Hemisphere, but a 47 percent plunge in 24 months would require death on a scale no chronicle, burial record or skeletal study comes close to showing. Population figures for the sixth century are estimates pieced together from scattered evidence, and they do not move like that. Treat the 190-million-to-100-million slide as a dramatic flourish, not a measurement.

The same caution applies to the framing around it. The claim that 536 and 537 together form "the worst period in human history" is a subjective superlative, not a settled finding. There is no scholarly consensus that crowns any single stretch of years as history's absolute low point, even though conditions in parts of the Northern Hemisphere during those months were genuinely brutal. The source's closing line, that many disasters past and present look idyllic next to the darkness of 536 and 537, is that same opinion dressed up as conclusion.

The takeaway is not that the Year 536 was mild. It is that the story gets more believable, and more chilling, when you strip away the invented statistics and let the real evidence speak.


## Frequently asked questions

**What happened in the year 536?**

In 536 a volcanic winter dimmed the Sun, cooled the climate, and triggered crop failure and famine across parts of the Northern Hemisphere. Ice-core and tree-ring research points to an aerosol veil that lasted roughly one to two years, making the Year 536 one of the coldest and darkest stretches of the last two millennia.

**Why was the year 536 considered the worst time in history?**

The original account calls the roughly 20-month span from early 536 to late 537 the worst period in human history. That label is a contested superlative, not scholarly consensus. Researchers agree the years were exceptionally grim across much of the Northern Hemisphere, yet "worst ever" is a judgment call rather than a measured finding.

**How did the Krakatoa and Ilopango eruptions cause a global dark age?**

They did not, at least not as the popular version tells it. The claim that Krakatoa and Ilopango erupted five months apart and plunged the world into darkness is rated false. Research instead points to a high-latitude eruption, or possibly a tropical one, as the source of the 536 volcanic winter.

**What did Procopius write about the sun in 536?**

The Byzantine historian Procopius described the Sun giving no brightness for about a year and shining like the Moon. The famous "diary" line about entering the 18th month is not a verified verbatim quote, so treat that exact wording with caution even though his broader account of a dimmed Sun is well known.

**Did the year 536 cause cannibalism and rickets?**

Later chronicles do report famine cannibalism in some regions, so hunger-driven horror stories have a documentary root. The specific claims that disabled people were killed and treated as food, and that 8 of every 10 babies were born with rickets, are not reliably documented, and the rickets figure is rated false.

**How much did the world population drop between 535 and 537?**

The original account claims a fall from about 190 million in 535 to about 100 million by 537. That roughly 47 percent decline in two years is rated false. A loss of that scale in such a short window is demographically implausible and unsupported by credible sources.

**Was the year 536 colder than the Little Ice Age?**

The source does not make that comparison, so this question cannot be answered from it. What the material does support is a sharp volcanic cooling around the Year 536, with a dimmed Sun and failed harvests, without ranking it against the Little Ice Age.

**What did Justinian I do about the famine in 537?**

The claim that Justinian I banned cannibalism by law in 537 as soon as he became emperor is rated false. He took the throne in 527, a decade earlier, and no well-established 537 law specifically banning cannibalism is tied to the crisis. Famine relief in that era remains far less tidy than the legend suggests. Editorial note: Details that remain unconfirmed, including the exact identity and location of the volcanoes involved, are presented as uncertain rather than settled fact.

Canonical: https://curio.madeda.com/year-536-the-volcanoes-that-darkened-the-sun/