Horseshoe to the modern hoof boot. Historians differ on the origin of the horseshoe. Because iron was a valuable commodity, and any worn out items were generally reforged and reused, it is difficult to locate clear archaeological evidence. Although some credit the Druids, there is no hard evidence to support this claim. In 1897 four bronze horseshoes with what are apparently nail holes were found in an Etruscan tomb dated around 400 B.C. The assertion by some historians that the Romans invented the "mule shoes" sometime after 100 BC is supported by a reference by Catullus who died in 54 BC.
Horseshoe vortex cause a horseshoe cloud to form. Horseshoe vortex The horseshoe vortex model is a simplified representation of the vortex system of a wing. In this model the wing vorticity is modelled by a bound vortex of constant circulation, travelling with the wing, and two trailing wingtip vortices, therefore having a shape vaguely reminiscent of a horseshoe. A starting vortex is shed as the wing begins to move through the fluid, which dissipates under the action of viscosity, as do the trailing vortices far behind the aircraft. The trailing wingtip vortices are responsible for the component of the downwash which creates