Note:  Do not rely on this information. It is very old.

Chevauxde Frise

Chevaux de Frise (lit. Friesland horses) denotes a contrivance for defending a barricade or a breach, or for impeding the advance of troops, especially of cavalry. It consists of a central horizontal axis studded with spears or spikes. In the English service this axis is an iron tube, with holes for the insertion of the spikes, which are, for the convenience of transport, conveyed within the tube. A similar instrument for impeding cavalry by wounding the feet and legs of the horses was known in classic times, and was also employed in mediaeval warfare. Tops of walls are sometimes fitted with a similar contrivance.