Look up: caligae

1. Caligae
   hobnail soled boots with cutwork straps worn by the Roman army; the nickname of the Roman emperor Gaius Julius Caesar Germanicus, Caligula, means 'little boots' and was bestowed upon him by his father's troops.
   Found on http://ablemedia.com/ctcweb/glossary/glo
   
   
2. caligae
   These were the sandals (caligae or military boots) worn by legionaries. They consisted of multi-layered soles reinforced with iron hob-nails, which were secured to the foot with a network of thongs which rose up the leg. They were stuffed with wool or fur during colder weather. Also a leather personnel carrier.
   Found on http://www.encyclo.co.uk/visitor-contrib
   
   
3. Caligae
   `Caligae` (Latin; singular caliga) are heavy-soled hob-nailed military boots worn by Roman legionary soldiers and auxiliaries throughout the Roman Republic and Empire. Worn by all ranks up to and including centurions, no other shoes in history stand as much symbol for the expansion of an empi...
   Found on http://en.wikipedia.org/wiki/Caligae