Who was the Roman god of fire and the forge?

Vulcan, whose name gives us volcano, vulcanise and Vulcanian eruptions. The Romans placed his forge under Mount Etna and explained eruptions as the smoke and sparks of a god at work, which is a reasonable inference from the evidence available.

He is the odd one out in the pantheon. The gods are beautiful and he is lame and ugly, thrown from Olympus by his own mother in the Greek version because she was ashamed of him - and he is also the only one who works. Everyone else on Olympus is aristocratic; Hephaestus, his Greek original, is a craftsman with a workshop, married to Aphrodite, who despises him.

The festival named for him supplied a phrase. The Vulcanalia in August involved throwing small fish onto bonfires, and the name survives in vulcanology and, indirectly, in the vulcanisation of rubber - Charles Goodyear's process of heating latex with sulphur, discovered when he dropped a mixture on a stove. His name is now on tyres made by a company he had nothing to do with, founded nearly forty years after he died in debt.