I read once that glass was supposed to have been invented in pre-Roman Britain, apparently the name ‘glass’ has Celtic roots. I now think it much more likely that glass-making was introduced to Britain although at a fairly early date.
I now realise it was the Phoenicians who discovered glass as they claimed, it makes sense as the essential ingredient natron (soda) would have been virtually absent in damp Britain.
Also the Welsh chronicles talk of someone called Hu Gadarn (or Hu the Mighty and various other names) who came to Britain ‘around the time of Abraham’ which would be perhaps 1800BC – almost four millennia ago. This leader was supposed to have introduced glass-making into Britain according to the chronicles. He was also supposed to be the same person as Hercules (I am not making this up) who I understand to be a Phoenician so it does seem to make sense. I am not suggesting that Hercules personally discovered glass-making.
There is no doubt that glass-making was happening in Britain before the Roman period as in the nineteenth century archaeologists dug up a glass-making site at Glastonbury which no doubt accounts for its name.
The Ancient British were also using enamel, a type of glass, in their jewellery and other ornaments.
However, the Ancient British did not seem to have used glass for anything practical like windows. One use for glass, it is said, was for a type of religious charm – the snake stone, probably quite similar to a large Victorian children’s marble although others say it was a naturally occurring fossil.