Draconarius

Strictly speaking, the word draconarius denotes the bearer of the military standard on which a dragon was represented.

[1] The term passed into Christian usage, and was applied to the bearer of the labarum in battle, and also to cross-bearers in church processions.

[2] From the conquered Dacians, the Romans in Trajan's time borrowed the dragon ensign which became the standard of the cohort as the eagle was that of the legion.

[3] Of Dacian, Sarmatian in origin, the draco was later generally introduced in the fourth century as a Roman standard.

It is thought that some form of whistle was mounted in the dragon's neck to make a terrifying noise when galloping.