[1] There are many variations, but the usual ingredients include leftover bread, cannellini beans, lacinato kale, cabbage and inexpensive vegetables such as carrot, beans, chard, celery, potatoes and onion.
It was originally made by reheating (or reboiling) the leftover minestrone or vegetable soup from the previous day with stale bread.
[3] Some sources date it back to the Middle Ages, when the servants gathered up food-soaked bread trenchers from feudal lords' banquets and boiled them for their dinners.
[1] It is a typical poverty food of peasant origin, whose name derives from the fact that the peasants cooked a large quantity of it (especially on Fridays, as it is a fasting food) and then re-boiled it on the following days (hence "ribollita").
[4] The dish is first documented in 1910, in L'arte cucinaria in Italia by Alberto Cougnet.