Caligae were footwear worn by Roman legionaries and centurions. Those were a form of forged sandals. Those did not cover fingers, they had a thick, nail-studded sole consisting of several layers of skin. The sandals were attached to the feet with straps covering the instep and lower leg. In addition, leather or metal uppers covering entirely the shin were worn.
Created to fight in the summer on the plain were light and comfortable. However, during expeditions to the rocky mountains, legionaries threaded clothes and cloth. In the winter, sandals were insulated with fabric or fur. The shoes were tailored taking into account the differences between the right and left foot, which was unusual at the time.
They gave them the nickname Emperor Caligula, who, as a little boy, was in the Rhine camp. Roman commander Germanicus, showed his son Caligula to his soldiers, dressed in costume of legionary.