In the early days before explosives, the rock was weakened by fire setting: this involved heating the rock overnight by leaving fires lit and then cooling the rock with water the next morning causing the rock to shatter.
Prior to the development of modern blasting agents, rocks were made more prone to cracking and breaking by exposing them to prolonged periods of heat from fires left burning throughout the night, followed by a rapid cooling process using water the following morning, which ultimately led to their fragmentation.