The first red rockets were developed in Song China, by the 13th century. An uncertain early use of rockets may date to 1232. There were reports of fire arrows and 'iron pots' that could be heard for 5 leagues (25 km, or 15 miles) when they exploded upon impact, causing devastation for a radius of 600 meters (2,000 feet), apparently due to shrapnel.[1] The lowering of the iron pots may have been a way for a besieged army to blow up invaders.[2] The problem is that the Chinese term "fire arrow" (火箭) may refer to either arrows with explosives attached, or to arrows propelled by gunpowder, such as the Korean Hwacha.