DURING the middle ages, the Muslims who fought crusaders with swords of Damascus steel had an edge - a very high-tech one. Their sabres contained carbon nanotubes.

From about AD 900 to AD 1750, Damascus sabres were forged from Indian steel called wootz. Peter Paufler of the Technical University of Dresden, Germany, and colleagues studied samples of a 17th-century sword under an electron microscope and found clear evidence of carbon nanotubes and even nanowires.

The researchers think that the sophisticated process of forging and annealing the steel formed the nanotubes and the nanowires, and could explain the amazing mechanical properties of the swords (Nature, vol 444, p 286).