Articles about musical instruments of all kinds - from violins to drums to guitars to pianos to keyboards to saxes to trumpets to... home :: cornets Cornets -- cousin of the trumpet family History of The Cornet The cornet was developed in late 1500�s by an instrument known as post horn. With the addition of valves to post horn, a new instrument was made with the name of cornet. In late 1900�s, it was replaced by the trumpet. Cornet was very much used in jaz..