A double-reed instrument which is the predecessor of, and similar in range to, the bassoon. However, the conical tube of the curtal is hollowed out of a single piece of wood and is not jointed.

The long, flat billet of maple, pear, box, etc., is bored from the bottom upwards along one side, and from the top downwards, for the wider part of the conical windway, on the other side. The two bores are connected at the bottom by a cut-away chamber closed by a plug of wood. The brass crook on which the double reed is placed is inserted into the narrower bore. The wider bore ends in a short flare, similar to that of the clarinet.

Although it is not known for sure where it originated, most believe it an Italian product from the second quarter of the 16th century. But it soon spread as far as England by the last quarter of the century. It was also known widely throughout Europe as the fagott.