The origin of Caligula's name. The young Gaius earned the nickname "Caligula" (meaning "little soldier's boot", the diminutive form of caliga, hob-nailed military boot) from his father's soldiers while accompanying him during his campaigns in Germania. Gaius Julius Caesar Augustus Germanicus, AD 12 - AD 41. Roman emperor. From Hutchinson's History of the Nations, published 1915.