The fires lit around London after the Gunpowder Plot failed were bonfires.
On 5 November 1605, people in London learned that Guy Fawkes had been discovered guarding explosives beneath the House of Lords. King James I’s Council allowed public celebrations of the king’s survival, provided they caused no danger or disorder. Bonfires quickly became a visible symbol of thanksgiving.
Parliament later formalised the commemoration through the Observance of 5th November Act 1605, creating an annual day of public thanksgiving. The tradition gradually developed into Guy Fawkes Night, also called Bonfire Night, with fireworks, processions and burning effigies.
Candles, lanterns and torches were used for lighting and appeared in some historical celebrations, but they are not the defining answer. The key custom was the lighting of large outdoor fires; later celebrations added fireworks and the familiar Guy effigy.