In the modern world, those who say the phrase "what has fallen is lost" usually wants to show that one should come to terms with the loss, it is useless to regret it. However, not everyone knows that this metaphor was a law several centuries ago. In the 11th century in Russia, the value of the trade duty from merchants was determined by the number of carts with goods. Using this rule, merchants tried to load each carriage as much as possible in order to pay less taxes.
Then the authorities went for a trick and declared that any thing dropped from the cart becomes the property of the state. No matter how thrifty merchants tied up their goods, still some of them fell out along the road and went to the city's income. After that, among the merchants, the expression "what fell from the cart is lost" became customary, which has survived to this day.