This burial mound was excavated in 1903, and apparently contained 8 m³ of ashes.

Här låg nämligen på den ursprungliga marken ett mycket intensivt lager af aska utbredt öfver ett vidsträckt, 20 kv. m. stort område, 5 m. i SV. NO. och öfver 4 m. i SO. NV. Asklagrets djup var 40 cm.

My translation:

Here lay on the bare ground a "very intensive" layer of ashes on a wide, 20 m² area, 5 m SW-NE and more than 4 m SE-NW. The depth of the ash-layer was 40 cm.

Some more quotes following comments:

I ofantligt stor myckenhet förekom här brända människoben. Jag har ej i någon graf tillvaratagit en så stor mängd.


Here was an extreme mass of burned human bones. I have never in any other grave found so many.

According to the formula in this paper that I found by random googling, 8 m³ of ashes could mean 2000 corpses.

(The mound was thought to be from the "Viking Age".)

Let us assume it was a mass burial, e.g. after a battle. Clearly there are many other possibilities, but I am interested in an "upper limit" on the number of human corpses, not the likelihood of this or that.

Assuming it is from AD 750, how well preserved would the ashes be? Could it be a much larger number of corpses because the layer has been compressed?

Anything else I am missing?

  • 2
    Premodern cremation is also (I believe) assisted. Normally the body is burned along with a lot of wood. The mass of ash is probably the bier.
    – MCW
    Oct 4, 2021 at 9:04
  • An article I looked at yesterday concerning cremation on pyres indicated 200-400kg of wood was needed for a cremation; 3-6 times the mass of the average body. This could indicate only 1/3 to 1/6 of the ash would be accounted for by human sources.
    – justCal
    Oct 4, 2021 at 11:34
  • An article at a geocaching site mentions the site as a boat burial site-an unusually deep ash layer was found that contained both boat rivets and burnt bones..
    – justCal
    Oct 4, 2021 at 11:52
  • Nordin thought so too: "Den döde vikingen har man satt i sin farkost, eller har man möjligen, att döma af de få nitnaglarna, med dessa endast antydt en sådan.", but who knows.
    – Tomas By
    Oct 4, 2021 at 19:12

1 Answer 1


Ashes won't compress over time by any significant amount - everything compressible has been burnt off, leaving just ... ashes. They may leach into ground water however, and then run off. That's a different matter, and would result in land subsidence. Since no land subsidence was noted at the site, let's assume no significant leaching.

So we can take the given volume as being pretty close to the original deposit - whatever the source.

Now my parents' ashes each fit in a box roughly 25cm x 10cm x 15cm, or about 4000 cm3. That is 1 / 2000 of the observed deposit, which suggests the author made the same observation I just did about the volume of ashes from a cremated person.

Modern crematoria are likely more efficient than pagan practices of over 1000 years ago - so that 2000 persons would be the upper limit. However as noted in a comment above by njuffa:

The Islamic traveler Ahmad ibn Fadlan wrote an eyewitness account of the burial of a Viking chieftain. He was burned in a ship together with a thrall girl who was killed just before setting the ship alight. Most of the ashes in such a case would be due to the wooden ship, not from the two corpses aboard.

  • Settling involves no loss of volume or mass, but merely a lowering of the center of mass. Ground subsidence due to leaching is due to - loss of volume and mass due to leaching by ground water. Oct 3, 2021 at 23:29
  • Is your calculation for modern cremations accurate? It seems to assume that naked bodies are burned alone, with any clothing or container? (A casket 'in this case' vs a Viking ship in the other example). Oct 4, 2021 at 6:40
  • 1
    On 'compression': if you just drop loose ashes as they come onto a pile, those would at first include a fair amount of air to be trapped with it in the pile. So my conclusion would be that over time rearrangement of the solid ash particles would of course lead to a certain compressability to be observable? The other thing would imo be time: if that pile wasn't 'one go', but in 'an open pit', filled as time goes by & as needed, a significant portion might be not just washed away by rain, but also by mere wind (unless you swiftly bind the ashes with a little water or other binder)? Oct 4, 2021 at 6:46
  • @LаngLаngС the bodies are burned with just their clothing and coffin. The fuel is natural gas, which leaves no ashes mixed with the body as the burners are external to the pyre (and gas burners leave no ashes anyway, only gasses). A wooden funeral pyre otoh can easily reach 8 cubic meters in size all on its own for a single person (and still does in places where such things are used, India and regions of Japan for example. I know a Japanese person who cremated her mother last year, the pyre was about that size, took 36 hours to cool down before the ashes were gathered and interned).
    – jwenting
    Nov 3, 2021 at 10:06
  • The claim that "Ashes won't compress over time..." is incorrect. Wood ashes DO compress: they are quite light and fluffy when the fire first burns out. This is because (among other factors) the wood contains a lot of air space that derives from the cellular structure. Did a practical experiment just now, and I can compress ash from my wood stove to 1/2 its volume using finger pressure alone. (This is of course just wood ash: I have no human ash to experiment with. But as pointed out in comments, cremation requires a lot of wood.)
    – jamesqf
    Nov 3, 2021 at 17:31

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