moving spirit

plural moving spirits

1. Someone who provides significant impetus or guidance in a given venture, movement, enterprise etc.

   A couple of years later, he met Timothy Duffy, who was the moving spirit behind the Music Maker Relief Foundation.

   2005 June 11, Tony Russell, The Guardian

   3 more examples

   At the beginning of the year 1804 the most formidable conspiracy which had yet threatened the government and the life of Napoleon was discovered. […] Georges Cadoudal, the Breton peasant, who was the very soul of the royalist party, was the moving spirit.

   1932, Duff Cooper, Talleyrand, Folio Society, published 2010, page 106

   We had formed a conspiracy against an unpopular and ignorant teacher. Its moving spirit [translating Seele] was a fellow-student who seems since then to have taken Henry VIII of England as his model.

   1999, Sigmund Freud, translated by Joyce Crick, The Interpretation of Dreams, Oxford, published 2008, page 163

   Pompadour was the moving spirit in the elegant refurbishment of most of the royal residences, and in the development of a number of minor residences such as Crécy, Bellevue and the Trianon, in all of which she indulged the king's penchant for intimacy and privacy.

   2002, Colin Jones, The Great Nation, Penguin, published 2003, page 131