Lilia (defense system)
Lilia (plural of lilium ) are rows of pitfalls laid out in quincunx patterns that the Roman armies dug in front of their defenses. The type of mines as the Rough Castle of the Antonine are particularly well preserved, were of Caesar in De Bello Gallico described 7,73,8. The obstacles consisted of pits about 0.9 m deep, laid out in a quincunx pattern, with pointed piles on the ground, which were covered with brushwood. They were called Lilium because of the similarity with the sequence of flowers of the flower species of the same name : Id ex similitudine floris lilium appellabant.