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 A♭2 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".