Naphtha was also used by the Abbasids in the 9th century, with special troops, the "naffāṭūn", who wore thick protective suits and used small copper vessels containing burning oil, which they threw onto the enemy troops. There is also a surviving 9th century Latin text, preserved at Wolfenbüttel in Germany, which mentions the ingredients of what appears to be Greek fire and the operation of the "siphōn"s used to project it. Although the text contains some inaccuracies, it clearly identifies the main component as naphtha. Resins were probably added as a thickener (the "Praecepta Militaria" refer to the substance as , "sticky fire"), and to increase the duration and intensity of the flame. A modern theoretical concoction included the use of pine tar and animal fat along with other ingredients.