Scholars believe that the "draco" was adopted by the Roman army following their conquest of the Dacians. Some scholars such as Osborne (1985) and Ashmore (1961) consider that the draco was adopted by the Romans from the Dacians. It became the standard of the cohort in the same way that the aquila or Imperial eagle was the standard of the Roman legion. The adopted standard in the Roman cavalry was borne by a draconarius. Later, the "draco" became an imperial ensign.