Which planet was excluded from Gustav Holst's composition “The Planets?”

The Planets, Op. 32, is a seven-movement orchestral suite by the English composer Gustav Holst, written between 1914 and 1916. Each movement of the suite is named after a planet of the Solar System and its corresponding astrological character as defined by Holst.

From its premiere to the present day, the suite has been enduringly popular, influential, widely performed and frequently recorded. The work was not heard in a complete public performance, however, until some years after it was completed.

The suite has seven movements, each named after a planet and its corresponding astrological character (see Planets in astrology):

Mars, the Bringer of War (1914)

Venus, the Bringer of Peace (1914)

Mercury, the Winged Messenger (1916)

Jupiter, the Bringer of Jollity (1914)

Saturn, the Bringer of Old Age (1915)

Uranus, the Magician (1915)

Neptune, the Mystic (1915).