engines during the Siege of Petra (550–551). the Mongols were known to fire containers of burning tar during sieges using catapults and trebuchets. Wheels could be covered in pitch, set alight, and rolled along; this technique was commonly used during the Crusades. The besieged Carthaginians in Motya, 398 BC, set alight the siege engines of the attacking Syracusan forces under Dionysius I by dropping burning charred logs and resin-soaked oakum; however, the Syracusans were able to put out the fires. Pitch was a base ingredient in many incendiary devices throughout the period. The Boeotians developed a fire machine, which they used against the Athenian wooden fortifications during the Battle of Delium in 424 BC. A cauldron of burning coals, pitch and sulfur was suspended at one end of a hollowed-out log and bellows were fixed to the other end. A similar mixture was used 1700 years later by the Scots, when they dropped bales of wood, tar and sulfur by crane onto the English "sow" (a large protective shield covering the battering ram) at the 1319 siege of Berwick-upon-Tweed. Animal renderings and parts At the 1215 siege of Rochester Castle, King John ordered that fat from 40 pigs be used to set fire to the mines beneath the keep, which caused it to collapse; a cheap and effective technique in place of the more complicated mixture of sulfur, tallow, gum, pitch and quicksilver he had used in France the previous year. Animal fat was not uncommon as an accelerant; in the 13th century French sortie-parties would often be equipped with animal fat, straw and flax to use as fuel when setting fires amongst enemy siege engines. There were some other intriguing uses of animal parts; during the Siege of Paris in 886 AD, the Franks dropped bucket-loads of a hot mixture of pitch (or oil), wax and fish on the attacking Vikings; the mixture got under the armour and stuck to the skin. Konrad Kyeser's Bellifortis of 1405 describes a poisonous mixture of sulfur, tar and horses' hooves. Other incendiary ingredients included egg yolks, and pigeon and sheep droppings. Some documented uses of animals were not thermal or incendiary. Live insects were also used, to sting the enemy. 4th century BC writer Aeneas Tacticus suggested defenders should let wasps and bees into enemy mines, and jars of scorpions were sometimes fired during early bombardment in naval battles. In 189 BC