triboli

A term for caltrops, which were used to obstruct enemies. They had four spikes, so arranged that one always stood upright, when they were thrown on the ground. Thousands could be strewn in front of a battle line or across a road and the thousands of spikes could cripple the feet of both infantry and, more importantly, charging cavalry

Triboli

Caltrops.
Found on http://www.encyclo.co.uk/local/20764
No exact match found