Correcting Reconstruction of Diocletian's Palace

[Aldarion]

Correcting Reconstruction of Diocletian’s Palace

There are several things wrong with the reconstruction seen in the post (featured) image. First, the location. Palace could not have been that close to the sea – under such conditions, sea will hav…

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There are several things wrong with the reconstruction seen in the post (featured) image.

First, the location. Palace could not have been that close to the sea – under such conditions, sea will have broken against the foundations of the seaside wall, causing the entire southern wall of the palace, and both towers, to eventually collapse. Romans will have known this, though they will not have been aware of the fact that Adriatic coast is sinking as European continental plate is subsiding itself under African one. As such, palace will have been located some meters, or tens of meters, away from the sea shore during Diocletian’s time. Only the rising sea level will have brought it to the shoreline (indeed, nowadays the entrance to the cellars is below sea level).

 

[skip.knox]

If that first point were correct, about the placement, then every coastal fortification would have fallen. But many still stand. I can't speak to the science and engineering; all I can do is observe that sea walls have stood for very long periods of time.

The placement could still be wrong,, for course, for other reasons. Don't we know where at least some of the foundations are?

 

[Mad Swede]

The key to the survival of a building this close to the sea is good foundations and regular maintenance. For an excellent example I refer you to Portus Adurni (now known as Portchester Castle), the best preserved Roman fort north of the Alps. Located by the sea just outside Portsmouth it was in constant use as a fortress and later castle from about 290AD to about 1815AD. Other later (Tudor) examples in the UK would be Calshot Castle, Yarmouth Castle and Hurst Castle.

 

[Aldarion]

If that first point were correct, about the placement, then every coastal fortification would have fallen. But many still stand. I can't speak to the science and engineering; all I can do is observe that sea walls have stood for very long periods of time.

The placement could still be wrong,, for course, for other reasons. Don't we know where at least some of the foundations are?

I said that it will have fallen because that is precisely what had happened. As sea level rose - or, rather, Croatian coast slowly sunk (no, it has nothing to do with climate change) - the southwestern tower was exposed to strong waves caused by lebićada and oštro (libeccio - SW wind, ostro - S wind), eventually leading to its collapse in the 15th century. Southeastern tower is still standing.

Coastal fortifications however tend to have (though not always, as Mad Swede said) some sort of protection against the elements: typically an embankment.

No such structure is visible in the construction of the palace. That being said, 16th century engraving does show what may be an embankment in front of the fort:

And placement isn't that difficult... palace itself is still standing. But since Croatian coast is sinking, it is difficult to estimate how far away from the sea it was during the time of Diocletian.

EDIT:

The key to the survival of a building this close to the sea is good foundations and regular maintenance. For an excellent example I refer you to Portus Adurni (now known as Portchester Castle), the best preserved Roman fort north of the Alps. Located by the sea just outside Portsmouth it was in constant use as a fortress and later castle from about 290AD to about 1815AD. Other later (Tudor) examples in the UK would be Calshot Castle, Yarmouth Castle and Hurst Castle.

From what I see, Porchester Castle also has couple of meters between the walls and the sea (though perhaps not as much as my reconstruction would give the palace). Calshot Castle is also some distance away from the sea, as is the Hurst Castle. Yarmouth Castle does have part of the wall in the water.

 

[pmmg]

If it took 1200 years to get the tower to collapse, I would say it did its job.

Ya know...1200 years is a long time to never say...how about we do something about this water.

 

[Aldarion]

If it took 1200 years to get the tower to collapse, I would say it did its job.

Ya know...1200 years is a long time to never say...how about we do something about this water.

At first, it will not have been an issue because tower will not have been in the water. By 16th century however water may have reached all the way to Mihovilova Širina:

Ul. Mihovilova širina · 21000, Grad, Split, Croatia

21000, Grad, Split, Croatia

www.google.com

And by the 14th / 15th centuries, there were bigger issues to worry about... like the Ottomans. And that is assuming damage was even noticed - if it was underwater, or if the water got underground and undermined foundations themselves, nothing may have been noticed until it was too late.

 

[skip.knox]

Is it possible that the sinking of the ground was more to blame than the action of water? I'm thinking here of numerous medieval buildings that collapse precisely because the ground under them sank, causing fractures.

In any case, the reconstruction of the palace as depicted in that image, couldn't that still be correct? That is, the seaward walls might have been at the water line?

Of course, with such pictures, it might also just be the artist taking liberties.

 

[Aldarion]

Is it possible that the sinking of the ground was more to blame than the action of water? I'm thinking here of numerous medieval buildings that collapse precisely because the ground under them sank, causing fractures.

In any case, the reconstruction of the palace as depicted in that image, couldn't that still be correct? That is, the seaward walls might have been at the water line?

Of course, with such pictures, it might also just be the artist taking liberties.

I guess sinking of the ground is a possible explanation. I've only ever heard of a wave-related damage explanation, though.

Reconstruction still couldn't have been correct, because today we actually do know where coastline was during Diocletian's time (of course, author of that reconstruction could not have known that):

Luka dioklecijanove palače / Port of Diocletian's palace

U istraživanjima splitske Rive 2006. – 2007. godine pronađeni su značajni nalazi zidanih struktura na temelju kojih je moguće u velikoj mjeri rekonstruirati izvorni izgled antičke obale ispred Dioklecijanove palače. Zahvaljujući ranijim analizama

www.academia.edu

Shoreline during Diocletian's time was some 12 meters from the seaward wall.

 

[Prince of Spires]

One interesting fact about Roman concrete is that sea water actually strengthens it, unlike with modern concrete. I don't know what materials were used for the palace, but this could played a role there as well. ( How seawater strengthens ancient Roman concrete | UNews )

 

[Aldarion]

One interesting fact about Roman concrete is that sea water actually strengthens it, unlike with modern concrete. I don't know what materials were used for the palace, but this could played a role there as well. ( How seawater strengthens ancient Roman concrete | UNews )

Walls actually consist of two external walls built from stone blocks which were then linked by either plaster, concrete or iron links / pegs that were then covered with molten lead. The core of the walls is broken stone linked with concrete (opus emplectum).

But that will not have stopped erosion, I think. Especially if, as skip.knox suspects, ground sank (either due to ingress of water or other factors).