- James W. McKinnon
A Roman brass instrument second only to the tuba (see Tuba) in importance (it is classified as an Aerophone). It consisted of a long bronze tube, curved into a shape resembling the letter ‘G’, the lower extremity having a large detachable mouthpiece and the upper having a flared bell projecting forwards horizontally. It was held in a nearly vertical position while an ornamented wooden bar extended from top to bottom, serving both as a grip and as a strengthening member. To judge from pictorial representations, it had a circumference of about 3 metres (see illustration).
Like the Lituus it appears to have been of Etruscan origin and, also like that instrument, is said to have been a later modification of the tuba, the straight trumpet. This hypothesis is quite plausible in view of the priority of the tuba; but it must be reconciled with another widely held view: that the cornu was originally an animal's horn like the ...