Bare cast-iron vessels have been used for cooking for hundreds of years. Cast iron cauldrons and cooking pots were treasured as kitchen items for their durability and their ability to retain heat, thus improving the quality of cooking meals. Before the introduction of the kitchen stove in the middle of the 19th century, meals were cooked in the hearth or fireplace, and cooking pots and pans were designed for use in the hearth. This meant that all cooking vessels had to be designed to be suspended on, or in, a fireplace. Cast iron pots were made with handles to allow them to be hung over a fire, or with legs so that they could stand up in the fireplace. In addition to dutch ovens, which were developed with the onset of the Industrial Revolution, a commonly used cast iron cooking pan called a spider had a handle and three legs used to stand up in the coals and ashes of the fire. Cooking pots and pans with legless, flat bottoms were designed when cooking stoves became popular; this period of the late 19th century saw the introduction of the flat cast iron skillet.