Did Roman Buildings have Glass Windows?

I ask because even Italy can be cold in the winter. The Romans made many things from glass (cups, pitchers, glasses, etc.).But did they ever master the technique of making large sheets of glass? I have read that they did use thin sheets of alabaster as windows, did they have glass windows as well?

I don’t have a cite handy, but, yes, glass windows have been found in Pompeiian houses.

Here’s a cite from the Metropolitan Museum of Art

This statement makes no sense. Why even have a window, then?

Yeah, the part about illumination doesn’t make sense to me. I thought the primary reasons ancient buildings dwellings/bath houses/etc would have windows is so they could enjoy the sunlight during the day and not have to waste lamp oil/candles, to provide a view of the outside, and to let in air in warmer months.

I can understand the Romans not caring if the glass was clear because the primary purpose of their windows probably wasn’t the view they offered. But even non-transparent glass would offer illumination, sunlight will go through opaque glass fairly well.

You got some illumination, yes, but people were using empty windows wth some covering for a long time for that. Having glass was a nice way to keep out the cold and damp from it.

[nitpick]If the glass is opaque, that means NO light goes through.[/nitpick]See Opaque

Perhaps you mean Translucent?

There are several reasons. Aesthetic, practical (although the primary purpose was not illumination the fact that they did provide some would have been a bonus). You’re imposing your idea of what a window is on to the Romans.

If you don’t want what I want in a window, then roman, persian, or whatever, what you want is either a door, or a wall.


Yes, I had some pieces that came from a dig at the Roman baths in the Cimiez (ex-Cimenelum) section of Nice, France, when I was there many years ago.

Fragments of window glass were found in archaeological excavation of a milecastle on Hadrian’s Wall, just west of Housesteads Fort. A milecastle was an entry point in the wall, manned by perhaps a dozen soldiers. So, window glass was available for a minor post on the extreme fringe of the Empire.
As I recall, the chunk I saw was maybe about the transparency of old-fashioned blue bottle glass. Light would come through easily, but you wouldn’t see much through it.
According to some of the exhibits at the Wall, glass was manufactured in large chunks elsewhere in the Roman Empire, where the proper raw materials were available, and then shipped where it was needed; it would then be re-melted and used as desired.

I believe the technique for producing window glass at that time would have consisted of blowing a large bottle, cutting off the ends (while still warm and pliable), slitting the resulting cylinder and flattening it.

I heard that glass is a liquid, and that’s why windows are thicker at the bottom…? is that true?


Only treadmill glass.

Not only did they have window glass but they had double glazing.
The fittings for double glazing have been found at the baths in Ostia(The port of Rome)

I think that technique is a later refinement that lets you make larger, flatter pieces. The classic technique (that was used quite late, into the 17th and even 18th century) was to take a big hot gob of molten glass on a blow tube, blow a large bubble, “pop” the end, then spin the glass into a disc. You ended up with a very large isc if you did it right. There would be varuiation in the thickness, but, again, not too much if the disc was big enough.

How do you blow a bottle shape?

Someone linked to an article on Renaissance Venetuian glassblowers doing thjis. You basically blow a bubble, then swing it so that it stretches out into a roughly cylindrical shape with a rounded end. You let it somewhat set, then set it down sideways on a resistant surface andcut it rapidly down the side and unroll it before it has a chance to stick together.

It strikes me as a highly skilled method that requires specialized equipment and a lot of space, and probablty a high balcony. I strongly suspect that the Blow-A-Bubble-and-Pop-It method (which is the only one they taught us about in school) was a heckuva lot easier and demanded less skill and equipment,.

Dip a pipe in your jar of molten glass, blow a bubble, then let gravity sag out the bubble into an oblong shape.

Some more general demo’s of blowing glass can be seen on YouTube.

The first known window, as we would know one today, was found in the ruins of Pompeii.Around 100AD, the Romans discovered that adding manganese dioxide to their glass mixture created clear cast glass, hence they could use it for window glass in their most important buildings in Rome, as well as their ‘holiday villas’ in Herculaneum and Pompeii; they later spread the idea of clear glass windows throughout their Empire.[/QUOTE

From here: