The tenor saxophone is a medium-sized member of the saxophone family, a group of instruments invented by Adolphe Sax in the 1840s. The tenor and the alto are the two most commonly used saxophones. The tenor is pitched in the key of B (while the alto is pitched in the key of E), and written as a transposing instrument in the treble clef, sounding an octave and a major second lower than the written pitch. Modern tenor saxophones which have a high F key have a range from A2 to E5 (concert) and are therefore pitched one octave below the soprano saxophone. People who play the tenor saxophone are known as "tenor saxophonists", "tenor sax players", or "saxophonists".