The name cornet derives from corne, meaning horn, itself from Latin 'cornu'. The modern-day cornet is used in brass bands, concert bands, and in specific orchestral repertoire that requires a more mellow sound. As several instrument builders made improvements to both instruments, they started to look and sound more alike. Symphonic repertoire often involves separate parts for trumpet and cornet. Up until the early 20th century, the trumpet and cornet co-existed in musical ensembles.
The first notable virtuoso player was Jean-Baptiste Arban, who studied the cornet extensively and published La grande méthode complète de cornet à piston et de saxhorn, commonly referred to as the Arban method, in 1864. Later, and most importantly, François Périnet received a patent in 1838 for an improved valve which is the basis of all modern brass instrument piston valves.
They jointly applied for a patent and were granted this for a period of ten years. These two instrument makers almost simultaneously invented valves, though it is likely that Blühmel (or Blümel) was the inventor, and Stölzel who developed a practical instrument. This instrument could not have been developed without the improvement of piston valves by Silesian horn player Friedrich Blühmel and Heinrich Stölzel in the early 19th century. Cornets first appeared as separate instrumental parts in 19th-century French compositions. However by the 1830s, Parisian makers were using piston valves. The cornet derived from the posthorn, by applying rotary valves to it in the 1820s in France.