People used to find big bargains at a “fire sale,” a term first applied to discounted fire-damaged goods. You may still find these, but the term now more often applies to financially troubled sellers trying to raise money quickly with very low prices.
When apprenticeships in trades were more common, a new and unskilled apprentice might be asked to hold a candle for light while his master worked his craft. Only a very useless apprentice “can’t hold a candle to” his master’s work and perform even this menial task, and the term also indicates the great disparity between the abilities of the two. A 16th-century writer who was among the first to use the term wrote that he was not worthy to hold a candle to Aristotle.
Working on a project late into the night? You likely have electric lights on, but in centuries past an oil lamp would have lit your work. This is the origin of the term “burning the midnight oil.”
You can’t return to where you were if you’ve “burnt all your bridges” behind you (or burnt all your boats). However, this idiom derives from a practice of the ancient Roman armies, so that the invading Romans knew that no retreat was available; victory or death were the only options.
One of several modern sayings derived from real torture methods of centuries past, “holding his feet to the fire” wasn’t just psychological pressure in the old days, but a much more unpleasant actual practice.
SOURCE: Pinker, Steven. The Better Angels of Our Nature, Why Violence Has Declined, New York, Penguin, 2011. (page i6)
“Bonfire of the Vanities” was a good book-turned-movie, named after a lesser-known historic practice. Starting in 1497, Dominican friar Girolama Savonarola wanted the citizens of Florence to prepare for the end of the world, which he expected in the year 1500. This was done by burning items which he felt distracted them from religious obligations, including scientific tools, “objectionable” artwork, musical instruments, classical literature, cosmetics, dresses, and more. These giant fires were later dubbed “Bonfires of the Vanities.” The less uptight Florentines grew tired of the friar, as did the pope he often criticized, and he was hanged with his body burned on the same spot as his bonfires occurred.
Your attention is too divided to concentrate on any one task if you “have too many irons in the fire.” This old idiom derived from blacksmithing, where having too many irons in the fire means no one can be given proper attention. This also causes the fire to cool, such that none of these irons will heat properly.